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Analysis of vector wind change with respect to time for Cape Kennedy, Florida
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
Multivariate analysis was used to determine the joint distribution of the four variables represented by the components of the wind vector at an initial time and after a specified elapsed time is hypothesized to be quadravariate normal; the fourteen statistics of this distribution, calculated from 15 years of twice-daily rawinsonde data are presented by monthly reference periods for each month from 0 to 27 km. The hypotheses that the wind component changes with respect to time is univariate normal, that the joint distribution of wind component change with respect to time is univariate normal, that the joint distribution of wind component changes is bivariate normal, and that the modulus of vector wind change is Rayleigh are tested by comparison with observed distributions. Statistics of the conditional bivariate normal distributions of vector wind at a future time given the vector wind at an initial time are derived. Wind changes over time periods from 1 to 5 hours, calculated from Jimsphere data, are presented. Extension of the theoretical prediction (based on rawinsonde data) of wind component change standard deviation to time periods of 1 to 5 hours falls (with a few exceptions) within the 95 percentile confidence band of the population estimate obtained from the Jimsphere sample data. The joint distributions of wind change components, conditional wind components, and 1 km vector wind shear change components are illustrated by probability ellipses at the 95 percentile level.
Analysis of vector wind change with respect to time for Cape Kennedy, Florida: Wind aloft profile change vs. time, phase 1
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
Wind vector change with respect to time at Cape Kennedy, Florida, is examined according to the theory of multivariate normality. The joint distribution of the four variables represented by the components of the wind vector at an initial time and after a specified elapsed time is hypothesized to be quadravariate normal; the fourteen statistics of this distribution, calculated from fifteen years of twice daily Rawinsonde data are presented by monthly reference periods for each month from 0 to 27 km. The hypotheses that the wind component changes with respect to time is univariate normal, the joint distribution of wind component changes is bivariate normal, and the modulus of vector wind change is Rayleigh, has been tested by comparison with observed distributions. Statistics of the conditional bivariate normal distributions of vector wind at a future time given the vector wind at an initial time are derived. Wind changes over time periods from one to five hours, calculated from Jimsphere data, are presented.
Vector wind profile gust model
NASA Technical Reports Server (NTRS)
Adelfang, S. I.; Evans, B. A.
A methodology was developed for the derivation and analysis of small scale perturbations in Jimsphere wind profiles. Gusts in various wavelength bands have been derived from these perturbations; the probability distribution of gust components and associated gust length has been shown to be accurately represented by a gamma distribution. Theoretical and observed distributions of component gust vary significantly with season, altitude, and wavelength range. The results of this study provide the basis for a vector wind model for Cape Kennedy, Florida.
Vector wind profile gust model
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
Work towards establishing a vector wind profile gust model for the Space Transportation System flight operations and trade studies is reported. To date, all the statistical and computational techniques required were established and partially implemented. An analysis of wind profile gust at Cape Kennedy within the theoretical framework is presented. The variability of theoretical and observed gust magnitude with filter type, altitude, and season is described. Various examples are presented which illustrate agreement between theoretical and observed gust percentiles. The preliminary analysis of the gust data indicates a strong variability with altitude, season, and wavelength regime. An extension of the analyses to include conditional distributions of gust magnitude given gust length, distributions of gust modulus, and phase differences between gust components has begun.
Vector wind profile gust model
NASA Technical Reports Server (NTRS)
Adelfang, S. I.; Smith, O. E.
The development of a vector wind gust model that is suitable for orbital flight test operations and trade studies was studied. Verification of the hypothesis that gust component variables are gamma distributed, gust modulus is approximately Weibull distributed, and zonal and meridional gust components are bivariate gamma distributed is emphasized. A method of testing for bivariate gamma distributed variables, and two distributions for gust modulus are described. The results of extensive hypothesis testing of one of the distributions are presented, and the validity of the gamma distribution for representation of gust component variables is established.
Vector wind profile gust model
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
To enable development of a vector wind gust model suitable for orbital flight test operations and trade studies, hypotheses concerning the distributions of gust component variables were verified. Methods for verification of hypotheses that observed gust variables, including gust component magnitude, gust length, u range, and L range, are gamma distributed and presented. Observed gust modulus has been drawn from a bivariate gamma distribution that can be approximated with a Weibull distribution. Zonal and meridional gust components are bivariate gamma distributed. An analytical method for testing for bivariate gamma distributed variables is presented. Two distributions for gust modulus are described and the results of extensive hypothesis testing of one of the distributions are presented. The validity of the gamma distribution for representation of gust component variables is established.
Wind Vectors for Hurricane Erin (WMS)
NSDL National Science Digital Library
Eric Sokolowsky
This visualization shows wind vectors for Hurricane Erin on September 10, 2001. Wind direction and speed are represented by the direction and speed of moving arrows, respectively. This animation represents a single measurement taken by the SeaWinds instrument on the QuikSCAT satellite, taken at 14:27:00 UTC on September 10, 2001. The WMS version of this animation which is available through the SVS Image Server (http:--aes.gsfc.nasa.gov) presents this animation with a different timestamp for each frame in order to more easily present the images as an animation. It should be noted that each frame really has a time stamp of 2001-09-10 14:27:00 UTC.
Vector wind and vector wind shear models 0 to 27 km altitude for Cape Kennedy, Florida, and Vandenberg AFB, California
NASA Technical Reports Server (NTRS)
Smith, O. E.
The techniques are presented to derive several statistical wind models. The techniques are from the properties of the multivariate normal probability function. Assuming that the winds can be considered as bivariate normally distributed, then (1) the wind components and conditional wind components are univariate normally distributed, (2) the wind speed is Rayleigh distributed, (3) the conditional distribution of wind speed given a wind direction is Rayleigh distributed, and (4) the frequency of wind direction can be derived. All of these distributions are derived from the 5-sample parameter of wind for the bivariate normal distribution. By further assuming that the winds at two altitudes are quadravariate normally distributed, then the vector wind shear is bivariate normally distributed and the modulus of the vector wind shear is Rayleigh distributed. The conditional probability of wind component shears given a wind component is normally distributed. Examples of these and other properties of the multivariate normal probability distribution function as applied to Cape Kennedy, Florida, and Vandenberg AFB, California, wind data samples are given. A technique to develop a synthetic vector wind profile model of interest to aerospace vehicle applications is presented.
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind-based power generation has been growing steadily in the United States and around the world, and this growth will continue�and accelerate�in the future, as the following background statistics demonstrate. The U.S. wind industry installed 8,358 megawatts (MW) of new wind generating capacity in 20...
Estimation of sea surface wind vector using RADARSAT data
Duk-jin Kim; Wooil M Moon
Synthetic aperture radars (SAR) have higher spatial resolution than scatterometers and we can obtain more detailed wind vector information from space-borne SAR data. This type of high spatial resolution wind information can be very useful particularly in coastal regions, where the scatterometer wind information can be altered by the coastal effects because the larger footprint spatial averaging of backscattered energy
User's Guide for Monthly Vector Wind Profile Model
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
The background, theoretical concepts, and methodology for construction of vector wind profiles based on a statistical model are presented. The derived monthly vector wind profiles are to be applied by the launch vehicle design community for establishing realistic estimates of critical vehicle design parameter dispersions related to wind profile dispersions. During initial studies a number of months are used to establish the model profiles that produce the largest monthly dispersions of ascent vehicle aerodynamic load indicators. The largest monthly dispersions for wind, which occur during the winter high-wind months, are used for establishing the design reference dispersions for the aerodynamic load indicators. This document includes a description of the computational process for the vector wind model including specification of input data, parameter settings, and output data formats. Sample output data listings are provided to aid the user in the verification of test output.
Study of wind change for the development of loads reduction techniques for the space shuttle
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
Wind change statistics are analyzed for Vandenberg AFB, California (VAFB) and Kennedy Space Center, Florida (KSC). Means and standard deviations of wind component change and vector wind change modulus within 3-9 and 9-16 km altitude bands are tabulated. The contribution to 3.5 hr wind component change by wind perturbations in various wavelength bands is evaluated. Probability distributions of maximum 3.5 hr wind change in an altitude band are presented and a model for wind change at a specified altitude is tested with data derived from six data bases from VAFB and Santa Monica, California.
Roski, R A
Redirecting physician incentives, providing universal coverage, improving access to meaningful information, and providing innovation are the key components to solving this crisis. Those changes must focus on true competition and innovative ideas, which we must provide. In the past, the innovation in health care has come from physicians, and physicians must provide it in the future. Now is the time for action. Once again, we can use the words of Theodor Geisel to inspire us: So ... Be your name Buxbaum or Bixby or Bray or Mordaci Ali Van Allen O'Shea, You're off to great places! Today is your day! Your mountain is waiting! So ... get on your way! No one could put it more clearly or succinctly than Dr. Seuss. Take his words to heart. The challenge lies before us, and the opportunities are endless. Just as Sidney Garfield revolutionized health care delivery more than 60 years ago, now is the time to introduce revolutionary changes of our own. Do not sit idly by while our health care system further deteriorates. Allow yourselves to be the innovative leaders that will give this country a new and better system of health care delivery. So remember, your mountain is waiting! Get on your way! PMID:8846586
Vector wind, horizontal divergence, wind stress and wind stress curl from SEASAT-SASS at one degree resolution
NASA Technical Reports Server (NTRS)
Pierson, W. J., Jr.; Sylvester, W. B.; Salfi, R. E.
Conventional data obtained in 1983 are contrasted with SEASAT-A scatterometer and scanning multichannel microwave radiometer (SMMR) data to show how observations at a single station can be extended to an area of about 150,000 square km by means of remotely sensed data obtained in nine minutes. Superobservations at a one degree resolution for the vector winds were estimated along with their standard deviations. From these superobservations, the horizontal divergence, vector wind stress, and the curl of the wind stress can be found. Weather forecasting theory is discussed and meteorological charts of the North Pacific Ocean are presented. Synoptic meteorology as a technique is examined.
Building a Climate Data Record for Ocean Vector Winds
NASA Astrophysics Data System (ADS)
Ricciardulli, L.; Meissner, T.; Wentz, F. J.
Scatterometers such as QuikSCAT and ASCAT are in principle well suited for providing climate-quality wind observations. They are very stable sensors, usually unaffected by satellite drifts or other issues that might affect the temporal stability of the wind time series. However, combining data from multiple scatterometers with the accuracy required for climate studies is a major challenge. Here we will review the challenges and progress made towards producing high-quality and consistent time series of ocean vector winds from past, current, and future scatterometer missions. We will describe the development of consistent Geophysical Model Functions (GMF) at the Ku-, C, and L-band frequencies, and the efforts in understanding and removing sources of bias among different scatterometer winds (i.e., atmospheric/ocean surface effects, rain impact, imperfect calibration of the GMF, etc..) . An additional and important source of inter-satellite bias at a regional level is due to the diurnal variability in the ocean surface winds. We will present an analysis aimed at estimating the amplitude and phase of wind diurnal variability. We will show how global time series of ocean winds from different scatterometer missions do overlap within the accuracy required for climate studies, when processed in a consistent manner and with proper quality control,.
Using Daily Ocean Wind Vector and Speed Measurements to Estimate the Diurnal Cycle Modes
NASA Astrophysics Data System (ADS)
Turk, F. J.; Hristova-Veleva, S. M.; Haddad, Z. S.
Over many oceanic regions, the surface wind varies widely throughout the day, owing to various meteorological forcings, such as land/sea temperature differences near coasts, or variations associated with tropical precipitation processes. Over the tropical oceans, several coarsely spaced buoy networks (TAO/TRITON in the Pacific, PIRATA in the Atlantic, RAMA in the Indian Ocean) are maintained as part of the Global Tropical Moored Buoy Array. For finer global scale analysis, further improvements to the modeling and understanding of physical processes within the coupled atmosphere ocean is based upon analysis of a disparate collection of low Earth orbiting (LEO) satellite based ocean surface wind data records. Since LEO satellite observations represent intermittently spaced, instantaneous snapshots, sampling against the backdrop of continuously changing physical processes, its is important to carefully merge and analyze the multiple satellite datasets in order to extract meaningful information on diurnal and semi-diurnal wind cycles. Early analysis of an investigation are described whereby multi-year collections of global sun-synchronous and asynchronous orbiting satellite ocean wind data are used to investigate the diurnal and semi-diurnal ocean wind vector variability over certain regions. A unique feature of the effort is the utilization of all capable sensors, including both wind speed and wind vector capable sensors, using overlapping asynchronous satellite observations to establish self-consistency, including inter-sensor bias correction to a common reference platform.
Designing Scatterometer Constellations for Sampling Global Ocean Vector Winds
NASA Astrophysics Data System (ADS)
Rodriguez, E.; Chelton, D. B.; Stoffelen, A.; Schlax, M.
The rapid temporal variations in ocean vector winds make it impossible to obtain synoptic global snapshots of winds and wind stress from a single spaceborne sensor. Even when multiple sensors are present, the peculiarities of the resulting space-time sampling pattern require that significant smoothing in space and time be performed to limit spatially and temporally inhomogeneous error characteristics in the merged data. Based on the collected common experience in its member states, the World Meteorological Organization collects requirements for spatio-temporal sampling in meteorological applications such as global and regional Numerical Weather Prediction, nowcasting, and climate. An additional concern, when constructing data sets from sun-synchronous missions, is that undersampling of diurnal and sub-diurnal variability may result in aliasing of the climate data record. Indeed, examination of climatologies constructed from different satellite missions, such as NASA's QuikSCAT and EUMETSAT's ASCAT scatterometers, show systematic differences that cannot be explained as being due solely to unresolved incoherent diurnal and sub-diurnal variability. Some of these differences, especially in the tropics, are probably explained by systematic diurnal and sub-diurnal variations. Other differences may be due to the difficulty of cross-calibrating sun-synchronous satellites with different local times. Forthcoming satellite missions may offer the possibility of overcoming or mitigating the space-time sampling and calibration challenges using multiple coordinated platforms. In the next decade, there is an expectation that ocean vector winds will be measured simultaneously by multiple satellites from the European community, India, China, and the United States. The coordination and suitable merging of the data from these satellites to produce a climate data record will be a challenge to the ocean vector winds community. In this presentation, we use climatologies constructed from multiple missions (NASA's QuikSCAT and SeaWinds on ADEOS-2, EUMETSAT's ASCAT, ISRO's OSCAT) that have overlapped over significant times to assess the impact of platform sampling and calibration characteristics on constructing consistent climatologies. We also extend the statistical simulation studies by Schlax et al. (2001) to include the effects of diurnal and sub-diurnal variations. Using these methods, we will examine a variety of potential platform configurations for future planned missions and assess their potential for producing a consistent ocean vector wind climate data record.
Triboelectric nanogenerator for harvesting wind energy and as self-powered wind vector sensor system.
Yang, Ya; Zhu, Guang; Zhang, Hulin; Chen, Jun; Zhong, Xiandai; Lin, Zong-Hong; Su, Yuanjie; Bai, Peng; Wen, Xiaonan; Wang, Zhong Lin
We report a triboelectric nanogenerator (TENG) that plays dual roles as a sustainable power source by harvesting wind energy and as a self-powered wind vector sensor system for wind speed and direction detection. By utilizing the wind-induced resonance vibration of a fluorinated ethylene-propylene film between two aluminum foils, the integrated TENGs with dimensions of 2.5 cm � 2.5 cm � 22 cm deliver an output voltage up to 100 V, an output current of 1.6 ?A, and a corresponding output power of 0.16 mW under an external load of 100 M?, which can be used to directly light up tens of commercial light-emitting diodes. Furthermore, a self-powered wind vector sensor system has been developed based on the rationally designed TENGs, which is capable of detecting the wind direction and speed with a sensitivity of 0.09 ?A/(m/s). This work greatly expands the applicability of TENGs as power sources for self-sustained electronics and also self-powered sensor systems for ambient wind detection. PMID:24044652
Relating the Proca Photon Mass and Cosmic Vector Potential via Solar Wind
Ryutov, D. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
The effect of the Proca photon mass m{sub ph} and cosmic vector potential A{sub C} on the dynamics of solar wind is considered. For large-enough values of the parameter A{sub C}m{sub ph}{sup 2}, the solar wind structure at a distance of approx40 AU from the Sun should change significantly with respect to the actual observed flow. The absence of such deviations gives an upper bound on the parameter A{sub C}m{sub ph}{sup 2} 9 orders of magnitude less than in laboratory experiments measuring torque on a toroidal magnet.
Relating the Proca photon mass and cosmic vector potential via solar wind.
Ryutov, D D
The effect of the Proca photon mass m(ph) and cosmic vector potential A(C) on the dynamics of solar wind is considered. For large-enough values of the parameter A(C)m(ph)(2), the solar wind structure at a distance of approximately 40 AU from the Sun should change significantly with respect to the actual observed flow. The absence of such deviations gives an upper bound on the parameter A(C)m(ph)(2) 9 orders of magnitude less than in laboratory experiments measuring torque on a toroidal magnet. PMID:20365977
Wind vector retrieval algorithm for Oceansat-2 scatterometer
NASA Astrophysics Data System (ADS)
Gohil, B. S.; Sarkar, Abhijit; Varma, A. K.; Agarwal, Vijay K.
The forthcoming Indian satellite Oceansat-2 to be launched in 2007 will carry a microwave scatterometer and an ocean colour monitor onboard. The scatterometer, a Ku-band pencil beam sensor similar to that onboard Quikscat satellite, will provide surface vector winds over global oceans with a two days repetivity. An algorithm for retrieving wind vector from scatterometer has been developed with a solution ranking criteria of minimum normalized standard deviation (NSD) of wind speeds derived using backscatter measurements through a geophysical model function (GMF). Using Quikscat observational geometry and QSCAT-1 GMF, simulation based evaluation of algorithm performance under different noise conditions and its comparison with standard algorithm known as Maximum Likelihood Estimator (MLE) algorithm have been performed. Besides having retrieval performance closely comparable with MLE, the present algorithm has quality and rain flagging provisions. Moreover, it is computationally efficient with least subjectivity on various retrieval related parameters. These features are equally desirable for the operational implementation. Results of simulation studies related to retrieval, quality control and rain flagging along with its implementation to limited Quikscat data are presented.
Ocean Surface Vector Wind: Research Challenges and Operational Opportunities
NASA Technical Reports Server (NTRS)
Halpern, David
The atmosphere and ocean are joined together over seventy percent of Earth, with ocean surface vector wind (OSVW) stress one of the linkages. Satellite OSVW measurements provide estimates of wind divergence at the bottom of the atmosphere and wind stress curl at the top of the ocean; both variables are critical for weather and climate applications. As is common with satellite measurements, a multitude of OSVW data products exist for each currently operating satellite instrument. In 2012 the Joint Technical Commission on Oceanography and Marine Meteorology (JCOMM) launched an initiative to coordinate production of OSVW data products to maximize the impact and benefit of existing and future OSVW measurements in atmospheric and oceanic applications. This paper describes meteorological and oceanographic requirements for OSVW data products; provides an inventory of unique data products to illustrate that the challenge is not the production of individual data products, but the generation of harmonized datasets for analysis and synthesis of the ensemble of data products; and outlines a vision for JCOMM, in partnership with other international groups, to assemble an international network to share ideas, data, tools, strategies, and deliverables to improve utilization of satellite OSVW data products for research and operational applications.
Fault diagnosis of direct-drive wind turbine based on support vector machine
NASA Astrophysics Data System (ADS)
An, X. L.; Jiang, D. X.; Li, S. H.; Chen, J.
A fault diagnosis method of direct-drive wind turbine based on support vector machine (SVM) and feature selection is presented. The time-domain feature parameters of main shaft vibration signal in the horizontal and vertical directions are considered in the method. Firstly, in laboratory scale five experiments of direct-drive wind turbine with normal condition, wind wheel mass imbalance fault, wind wheel aerodynamic imbalance fault, yaw fault and blade airfoil change fault are carried out. The features of five experiments are analyzed. Secondly, the sensitive time-domain feature parameters in the horizontal and vertical directions of vibration signal in the five conditions are selected and used as feature samples. By training, the mapping relation between feature parameters and fault types are established in SVM model. Finally, the performance of the proposed method is verified through experimental data. The results show that the proposed method is effective in identifying the fault of wind turbine. It has good classification ability and robustness to diagnose the fault of direct-drive wind turbine.
Two-component vector wind fields by scanning aerosol lidar
NASA Astrophysics Data System (ADS)
Mayor, S. D.; Derian, P.; Hamada, M.; Mauzey, C. F.
Observations of two or more wind components that resolve turbulent perturbations over large areas remain a challenge in the atmospheric boundary layer community. One successful approach to multi-component flow measurement in the engineering community is particle image velocimetry (PIV). This presentation will report on recent progress in the development and validation of two motion estimation algorithms that can be applied to aerosol backscatter imagery to provide two-component horizontal wind fields. The algorithms being developed and tested are a traditional cross-correlation method (i.e., Schols & Eloranta, JGR, 1992) and a new wavelet-based optical flow method (D�rian et al., NMTMA, 2013). These algorithms have been applied to imagery from the Raman-shifted Eye-safe Aerosol Lidar (REAL) collected in Dixon, California, in 2007 (as part of CHATS) and in Chico, California in 2013. The resulting 2-component winds were compared against the same from sonic anemometers and a Doppler lidar. Our results include new insights on the performance of the cross-correaltion algorithm and new experiences with wavelet-based optical flow. Animations of turbulent flow in the atmospheric surface layer over approximately 10-square km areas with 15 s frame update rates will be presented. (Vectors may be spaced as closely as every 10 m, but the spatial resolution is larger and dynamic and related to the availability of small scale aerosol features in the imagery.) In addition to flow visualizations, time-series and space-series comparisons of the wind components with those from sonic anemometer and Doppler lidar data will be presented.
Vector control of the Brushless Doubly-Fed Machine for wind power generation
Shiyi Shao; Ehsan Abdi; Richard McMahon
The brushless Doubly-Fed Machine (BDFM) shows commercial benefits in the wind power generation. This paper presents a vector control scheme for the BDFM operating as a variable speed generator (VSG). The proposed vector controller is developed on the power winding stator flux frame, and can be used to control both speed and reactive power. The machine model and the control
Single-Vector Calibration of Wind-Tunnel Force Balances
NASA Technical Reports Server (NTRS)
Parker, P. A.; DeLoach, R.
An improved method of calibrating a wind-tunnel force balance involves the use of a unique load application system integrated with formal experimental design methodology. The Single-Vector Force Balance Calibration System (SVS) overcomes the productivity and accuracy limitations of prior calibration methods. A force balance is a complex structural spring element instrumented with strain gauges for measuring three orthogonal components of aerodynamic force (normal, axial, and side force) and three orthogonal components of aerodynamic torque (rolling, pitching, and yawing moments). Force balances remain as the state-of-the-art instrument that provide these measurements on a scale model of an aircraft during wind tunnel testing. Ideally, each electrical channel of the balance would respond only to its respective component of load, and it would have no response to other components of load. This is not entirely possible even though balance designs are optimized to minimize these undesirable interaction effects. Ultimately, a calibration experiment is performed to obtain the necessary data to generate a mathematical model and determine the force measurement accuracy. In order to set the independent variables of applied load for the calibration 24 NASA Tech Briefs, October 2003 experiment, a high-precision mechanical system is required. Manual deadweight systems have been in use at Langley Research Center (LaRC) since the 1940s. These simple methodologies produce high confidence results, but the process is mechanically complex and labor-intensive, requiring three to four weeks to complete. Over the past decade, automated balance calibration systems have been developed. In general, these systems were designed to automate the tedious manual calibration process resulting in an even more complex system which deteriorates load application quality. The current calibration approach relies on a one-factor-at-a-time (OFAT) methodology, where each independent variable is incremented individually throughout its full-scale range, while all other variables are held at a constant magnitude. This OFAT approach has been widely accepted because of its inherent simplicity and intuitive appeal to the balance engineer. LaRC has been conducting research in a "modern design of experiments" (MDOE) approach to force balance calibration. Formal experimental design techniques provide an integrated view to the entire calibration process covering all three major aspects of an experiment; the design of the experiment, the execution of the experiment, and the statistical analyses of the data. In order to overcome the weaknesses in the available mechanical systems and to apply formal experimental techniques, a new mechanical system was required. The SVS enables the complete calibration of a six-component force balance with a series of single force vectors.
Winds of change?: Projections of near-surface winds under climate change scenarios
S. C. Pryor; J. T. Schoof; R. J. Barthelmie
Changes in near-surface wind speeds due to global climate change may have profound geophysical and societal impacts. However, Global Climate Models (GCMs) are unable to replicate the historically observed magnitude and spatial variability of wind speeds, so we apply a downscaling technique to generate probability distributions of wind speeds at sites in northern Europe for historical periods (1961-1990 and 1982-2000)
Climate Change: Potential Affect on Pesticide Application for Vector Control
Technology Transfer Automated Retrieval System (TEKTRAN)
Global climate change has and will in the future contribute to the global burden of vector-borne disease by affecting the spatial and tempral distribution of disease. These changes in disease distributions are a direct result of altering the ecology of immature and adult habitats of insect vectors....
The relationship between wind vector and normalized radar cross section used to derive Seasat-A Satellite Scatterometer winds
NASA Technical Reports Server (NTRS)
Schroeder, L. C.; Jones, W. L.; Boggs, D. H.; Halberstam, I. M.; Dome, G.; Pierson, W. J.; Wentz, F. J.
The Seasat-A Satellite Scatterometer (SASS) ocean normalized radar cross section (NRCS) dependence on the 19.5-m neutral stability wind vector may be specified as a function of radar incidence angle, the angle between wind direction and radar azimuth, and the neutral stability wind speed expressed in m/sec at a height of 19.5 m. An account is given of the development of models both expressing this relationship and providing the basis of inversion of NRCS to SASS winds, from initially aircraft scatterometer measurement-based forms to three Seasat field-validation experiments which furnish model NRCS versus surface windspeed data for comparison with SASS data.
Short-Term Wind Energy Forecasting Using Support Vector Regression
Oliver Kramer; Fabian Gieseke
\\u000a Wind energy prediction has an important part to play in a smart energy grid for load balancing and capacity planning. In this\\u000a paper we explore, if wind measurements based on the existing infrastructure of windmills in neighbored wind parks can be learned\\u000a with a soft computing approach for wind energy prediction in the ten-minute to six-hour range. For this sake
Monuments in the winds of change
In Europe, nineteenth-century historicism, with its conscious association of the past with the present, initiated a veritable flood of public monuments - the cities were literally stuffed full of architectural sculpture and statues. At the end of the nineteenth and beginning of the twentieth century, Ljubljana was caught up in the winds of change and started to replace its German
Removing wave effects from the wind stress vector
Karl F. Rieder; Jerome A. Smith
The presence of ocean surface waves has been observed to affect both the magnitude and direction of the wind stress. Here concurrent wind and wave data are employed to study their relationship. To help isolate the influence of the waves, the wind stress is broken into three frequency bands: \\
Removing wave effects from the wind stress vector
Karl F. Rieder; Jerome A. Smith
The presence of ocean surface waves has been observed to affect both the magnitude and direction of the wind stress. Here concurrent wind and wave data are employed to study their relationship. To help isolate the influence of the waves, the wind stress is broken into three frequency bands: ``low'' (frequencies below 0.06 Hz), corresponding to large-scale motions in the
Normal vector and winding number in 2D digital images with their application for hole detection
Franck Xia
Differentiating hole from component is an important issue in digital topology. In a recent paper, Lee, Poston, and Rosenfeld proposed a method to distinguish external and internal boundaries in 2D and 3D images relying on the property of normal vector and winding number. The method uses a smoothing function to replace digital lattice for calculating normal vector on image boundary.
The Dependence of Ocean Surface Emissivity on Wind Vector as Measured with TMR
NASA Technical Reports Server (NTRS)
Tran, N.; Vandemark, D.; Ruf, C.; Zukor, Dorothy (Technical Monitor)
Global TMR brightness temperature observations at 18, 21, and 37 GHz have been colocated with near-simultaneous SeaWinds wind vector data as well as with a monthly SST climatological product. The combined data allow us to study the dependence of ocean surface emissivity, at each frequency, upon both wind speed and direction. Results show a clear two-branch wind speed dependence; weak and linear below 6 m/s with an abrupt increase in sensitivity above that point. Our analysis also shows that the nadir-view ocean surface emissivity depends on the angle between the wind direction and TMR's antenna polarization orientation.
Time changes in gradient and observed winds�
Carlson, Ronald Dale
. ANALYTICAL APPROACH. 13 a. The grid system. b. Data interpolation to the grid. . 13 c. Evaluation of the gradient wind and its components. 14 1) Height gradient 2) Trajectory curvature. 14 15 d. Evaluation of time changes. 17 e. Output 17 vii... & / d) 1200 GKC )10 v) 20 0 ~ /// 40 ~ & / / I l / I / I 4d , 4 40 4 e) 500 GNT Fig. 6. Observed and gradient wind speeds at the 500-mb level on 19 February 1964. (Ticked lines outline areas of non-gradient balance. ) 35 / / i 30 20...
Validation of QSCAT vector winds with air-sea interaction spar fluxes
H. C. Graber; M. Caruso; V. J. Cardone; M. A. Donelan
A colocated data set of QSC AT wind vector and sigma-o data with wind and wave ocean buoy observations from the NDBC buoy network in the Atlantic and Pacific oceans and Gulf of Mexico and Hawaiian Islands is assembled for validation. Also included are wind stress and high-resolution directional wave measurements from three air-sea interaction spar buoys off the coast
Measuring the Wind Vector Using the Autonomous Mini Aerial Vehicle M2AV
Aline van den Kroonenberg; Tim Martin; Marco Buschmann; Jens Bange; Peter V�rsmann
The meteorological mini unmanned aerial vehicle (M2AV) was used for measuring the meteorological wind. The wind is the vector difference between the aircraft speed relative to the earth (inertial velocity) and relative to the airflow (true airspeed). The latter was computed from five-hole-probe pressure mea- surements in combination with calibration-coefficient polynomials obtained during wind tunnel calibration. The aircraft inertial velocity,
NSDL National Science Digital Library
Dray, Tevian
Vector fields are vectors which change from point to point. A standard example is the velocity of moving air, in other words, wind. For instance, the current wind pattern in the San Francisco area can be found at . This site has a 2-dimensional representation; careful reading of the webpage will tell you at what elevation the wind is shown. How would you represent a vector field in 3 dimensions? What features are important? Some simple examples are shown. Each can be rotated by clicking and dragging with the mouse. Explore!
Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA
NASA Astrophysics Data System (ADS)
Griffiths, Peter G.; Webb, Robert H.; Fisher, Mark; Muth, Allan
Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10� more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.
Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA
Griffiths, P.G.; Webb, R.H.; Fisher, M.; Muth, A.
Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10� more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.
Control strategies for enhanced power smoothing in wind energy systems using a flywheel driven by a vector-controlled induction machine
Roberto C�rdenas; Rub�n Pe�a; Greg Asher; Jon Clare
This paper presents a novel control strategy for power smoothing in wind energy applications, especially those feeding a stand-alone load. The system is based on a vector-controlled induction machine driving a flywheel and addresses the problem of regulating the DC-link system voltage against both input power surges\\/sags from a wind turbine or sudden changes in load demand. The control is
Multidecadal Consistent Ocean Vector Winds: from QuikSCAT to RapidScat and Beyond
NASA Astrophysics Data System (ADS)
Rodriguez, E.; Hristova-Veleva, S. M.
There are multiple indications that wind circulation characteristics may have been changing over the last decades. However, obtaining a globally consistent high-accuracy assessment of these changes from spaceborne remote sensing data has proved elusive in many cases, even though ocean vector wind data has been collected from space starting in the 1990's. The reason that a consistent assessment of these changes is still a work in progress is due to multiple factors. Firstly, many of the scatterometer instruments were designed to meet accuracies satisfactory for weather prediction, not for the smaller magnitude changes associated with climate change. Nevertheless, these instruments have proven at least self-consistent over long periods and suggest that climate signals may be retrievable from their data. Secondly, the instruments have used different microwave frequency bands, and uncertainties still remain regarding the consistency of the measurement physics across frequency bands. Thirdly, the data have been processed differently with different, and potentially inconsistent, model functions. Finally, and perhaps most importantly, all of these satellites have been in sun-synchronous orbits, with observations being made at different local times. These differences in observation time leads to aliasing of diurnal and semi-diurnal observations into the climate data record. In the first part of this talk, I review our current state of knowledge of the intercalibration of the three major scatterometers of the past decades: NASA's QuikSCAT, EUMETSAT's ASCAT (A & B), and ISRO's OSCAT. In the second part, I describe the design of the NASA ISS-RapidScat cross-calibration mission. This mission uses the non-sun-synchronous characteristics of the International Space Station (ISS) orbit to provide coincident data with scatterometers in the constellation every revolution. It is expected that it will be able to provide cross-calibration cross section and wind data for QuikSCAT, ASCAT, and the forthcoming ISRO ScatSat mission. RapidScat is expected to launch in September, 2014, and the final part of this talk will present the first results of the mission on orbit.
Power smoothing in wind generation systems using a sensorless vector controlled induction Machine driving a flywheel
Roberto C�rdenas; Rub�n Pe�a; Greg Asher; Jon Clare
This paper presents a novel control strategy for power smoothing in generation systems in which power flow variations can occur. These variations are the norm in wind energy generation. The system is based on a sensorless vector controlled induction machine driving a flywheel. The induction machine is controlled to operate in a wide speed range by using flux weakening above
[Vector transmitted diseases and climate changes in Europe].
Rossati, Antonella; Bargiacchi, Olivia; Kroumova, Vesselina; Garavelli, Pietro Luigi
The increase in temperatures recorded since the mid-nineteenth century is unprecedented in the history of mankind. The consequences of climate changes are numerous and can affect human health through direct (extreme events, natural disasters) or indirect (alteration of the ecosystem) mechanisms. Climate changes have repercussions on ecosystems, agriculture, social conditions, migration, conflicts and the transmission mode of infectious diseases. Vector-borne diseases are infections transmitted by the bite of infected arthropods such as mosquitoes, ticks, triatomines, sand flies and flies. Epidemiological cornerstones of vector-borne diseases are: the ecology and behaviour of the host, the ecology and behaviour of the vector, and the population's degree of immunity. Mosquito vectors related to human diseases mainly belong to the genus Culex, Aedes and Mansonia. Climate changes in Europe have increased the spread of new vectors, such as Aedes albopictus, and in some situations have made it possible to sustain the autochthonous transmission of some diseases (outbreak of Chukungunya virus in northern Italy in 2007, cases of dengue in the South of France and in Croatia). Despite the eradication of malaria from Europe, anopheline carriers are still present, and they may allow the transmission of the disease if the climatic conditions favour the development of the vectors and their contacts with plasmodium carriers. The tick Ixodes ricinus is a vector whose expansion has been documented both in latitude and in altitude in relation to the temperature increase; at the same time the related main viral and bacterial infections have increased. In northern Italy and Germany, the appearance of Leishmaniasis has been associated to climatic conditions that favour the development of the vector Phlebotomus papatasi and the maturation of the parasite within the vector, although the increase of cases of visceral leishmaniasis is also related to host immune factors, particularly immunodepression caused by the human immunodeficiency virus (HIV). Despite the importance of global warming in facilitating the transmission of certain infectious diseases, due consideration must be taken of the role played by other variables, such as the increase in international travel, migration and trade, with the risk of importing parasites and vectors with the goods. In addition, the control of certain infections was possible in the past through improvements in socio-economic conditions of affected populations. However, the reduction in resources allocated to health care has recently led to the re-emergence of diseases that were considered eradicated. PMID:25269959
Global climate change and vector-borne diseases
Ginsberg, H.S.
Global warming will have different effects on different diseases because of the complex and idiosynchratic interactions between vectors, hosts, and pathogens that influence transmission dynamics of each pathogen. Human activities, including urbanization, rapid global travel, and vector management, have profound effects on disease transmission that can operate on more rapid time scales than does global climate change. The general concern about global warming encouraging the spread of tropical diseases is legitimate, but the effects vary among diseases, and the ecological implications are difficult to predict.
The Effect of the Arbitrary Level Assignment of Satellite Cloud Motion Wind Vectors on Wind Analyses in the Pre-thunderstorm Environment
Cynthia A. Peslen; Steven E. Koch; Louis W. Uccellini
The impact of satellite-derived cloud motion vectors (CMVs) on analysts of winds measured by rawinsondes during the 1979 SESAME Experiment is studied in two case studies (10 April and 9 May 1979). Cloud motion vectors are both arbitrarily assigned and vertically interpolated to typical `low' levels of 825 mb and = 0.9 before being combined with the rawinsonde-measured winds at
Lawrence, Rick L.
image, and change vector analysis (CVA) was used to identify locations where wetland areas might have Landsat image using SGB. Areas of change constituted 3.4% of the study area, thus only this small percentage of the image was reclassified for the 1988 image. Overall change detection accuracy was 76
Two-Dimensional Vector Wind Fields from Volume Imaging Lidar Data.
NASA Astrophysics Data System (ADS)
Mayor, Shane D.; Eloranta, Edwin W.
Spatially resolved wind fields are derived by cross correlation of aerosol backscatter data from horizontal and vertical scans of the University of Wisconsin volume imaging lidar during the 1997/98 Lake-Induced Convection Experiment. Data from three cases are analyzed. The first two cases occurred on 10 and 13 January 1998 during cold-air outbreaks. Horizontal scans at 5 m above the lake reveal cellular structure of the steam fog. Vector winds are derived with 250-m spatial resolution over 60 and 36 km2 areas. These wind fields show acceleration and veering of offshore flow in the convective internal boundary layer along the upwind edge of Lake Michigan. The wind fields are used to compute divergence and vorticity. Effects of shoreline shape and topography are evident in the data. Horizontal wind speeds derived from vertical scans show the effects of convection on the vertical distribution of momentum. In the third case, 21 December 1997, a well-defined, shallow density current flowing offshore at 1 m s1 is observed in the presence of larger-scale (3-4 m s1) onshore flow. Winds on both sides of the land-breeze boundary as well as the three-dimensional structure of the event were recorded and analyzed.
Effects of Changing Atmospheric Conditions on Wind Turbine Performance (Poster)
Clifton, A.
Multi-megawatt, utility-scale wind turbines operate in turbulent and dynamic winds that impact turbine performance in ways that are gradually becoming better understood. This poster presents a study made using a turbulent flow field simulator (TurbSim) and a Turbine aeroelastic simulator (FAST) of the response of a generic 1.5 MW wind turbine to changing inflow. The turbine power output is found to be most sensitive to wind speed and turbulence intensity, but the relationship depends on the wind speed with respect to the turbine's rated wind speed. Shear is found to be poorly correlated to power. A machine learning method called 'regression trees' is used to create a simple model of turbine performance that could be used as part of the wind resource assessment process. This study has used simple flow fields and should be extended to more complex flows, and validated with field observations.
Aspects of the determination of winds by means of scatterometry and of the utilization of vector wind data for meteorological forecasts
NASA Technical Reports Server (NTRS)
Pierson, W. J., Jr.; Sylvester, W. B.; Donelan, M. A.
The present paper provides a description of four aspects of scatterometer winds and their uses. The theory of wave generation by the wind is considered along with an analysis of the properties of superobservations, and studies of intermittent versus continuous data assimilation methods for numerical weather predictions which use remotely sensed data. A comparison of the sum of squares versus the maximum likelihood method for recovering the vector winds is also conducted. Questions regarding wind speed, friction velocity, or normal stress are discussed and synoptic scale fields from Seasat-SASS data are examined.
Using support vector machines for anomalous change detonation
Theiler, James P [Los Alamos National Laboratory; Steinwart, Ingo [UNIV STUTTGART; Llamocca, Daniel [UNM
We cast anomalous change detection as a binary classification problem, and use a support vector machine (SVM) to build a detector that does not depend on assumptions about the underlying data distribution. To speed up the computation, our SVM is implemented, in part, on a graphical processing unit. Results on real and simulated anomalous changes are used to compare performance to algorithms which effectively assume a Gaussian distribution. In this paper, we investigate the use of support vector machines (SVMs) with radial basis kernels for finding anomalous changes. Compared to typical applications of SVMs, we are operating in a regime of very low false alarm rate. This means that even for relatively large training sets, the data are quite meager in the regime of operational interest. This drives us to use larger training sets, which in turn places more of a computational burden on the SVM. We initially considered three different approaches to to address the need to work in the very low false alarm rate regime. The first is a standard SVM which is trained at one threshold (where more reliable estimates of false alarm rates are possible) and then re-thresholded for the low false alarm rate regime. The second uses the same thresholding approach, but employs a so-called least squares SVM; here a quadratic (instead of a hinge-based) loss function is employed, and for this model, there are good theoretical arguments in favor of adjusting the threshold in a straightforward manner. The third approach employs a weighted support vector machine, where the weights for the two types of errors (false alarm and missed detection) are automatically adjusted to achieve the desired false alarm rate. We have found in previous experiments (not shown here) that the first two types can in some cases work well, while in other cases they do not. This renders both approaches unreliable for automated change detection. By contrast, the third approach reliably produces good results, but at the cost of larger computational requirements caused by the need to estimate very small false alarm rates. To address these computational requirements, we employ a recently developed in-house solver for SVMs that is significantly faster than freely available standard solvers. But these computational issues are secondary to the larger question: do kernelized solutions provide better performance, in terms of detection rates and false alarm rates, than more traditional methods for change detection that effectively assume Gaussian data distributions? To this end, we will compare ROC curves obtained from the SVM with those from chronochrome, covariance equalization, and hyperbolic anomalous change detection.
Solar Wind Change Exchange from the Magnetosheath
NASA Technical Reports Server (NTRS)
Snowden, Steve
We report the results of a long (approximately 100 ks) XMM-Newton observation designed to observe solar wind charge exchange emission (SWCX) from Earth's magnetosheath. By luck, the observation took place during a period of minimal solar wind flux so the SWCX emission was also minimal. Never-the-less, there is a significant if not stunning correlation between the observed O VIII count rate and our model for magnetosheath emission. We also report on the observed O VII and O VII emission.
Evaluation and Validation of Operational RapidScat Ocean Surface Vector Winds
NASA Astrophysics Data System (ADS)
Chang, Paul; Jelenak, Zorana; Soisuvarn, Seubson; Said, Faozi; Sienkiewicz, Joseph; Brennan, Michael
NASA launched RapidScat to the International Space Station (ISS) on September 21, 2014 on a two-year mission to support global monitoring of ocean winds for improved weather forecasting and climate studies. The JPL-developed space-based scatterometer is conically scanning and operates at ku-band (13.4 GHz) similar to QuikSCAT. The ISS-RapidScat's measurement swath is approximately 900 kilometers and covers the majority of the ocean between 51.6 degrees north and south latitude (approximately from north of Vancouver, Canada, to the southern tip of Patagonia) in 48 hours. RapidScat data are currently being posted at a spacing of 25 kilometers, but a version to be released in the near future will improve the postings to 12.5 kilometers. RapidScat ocean surface wind vector data are being provided in near real-time to NOAA, and other operational users such as the U.S. Navy, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the Indian Space Research Organisation (ISRO) and the Royal Netherlands Meteorological Institute (KNMI). The quality of the RapidScat OSVW data are assessed by collocating the data in space and time with "truth" data. Typically "truth" data will include, but are not limited to, the NWS global forecast model analysis (GDAS) fields, buoys, ASCAT, WindSat, AMSR-2, and aircraft measurements during hurricane and winter storm experiment flights. The standard statistical analysis used for satellite microwave wind sensors will be utilized to characterize the RapidScat wind vector retrievals. The global numerical weather prediction (NWP) models are a convenient source of "truth" data because they are available 4 times/day globally which results in the accumulation of a large number of collocations over a relatively short amount of time. The NWP model fields are not "truth" in the same way an actual observation would be, however, as long as there are no systematic errors in the NWP model output the collocations will converge in the mean for winds between approximately 3-20 m/s. The NWP models typically do not properly resolve the very low and high wind speeds in part due to limitations of the spatial scales they can account for. Buoy measurements, aircraft-based measurements and other satellite retrievals can be more directly compared on a point-by-point basis. The RapidScat OSVW validation results will be presented and discussed. Utilization examples of these data in support of NOAA's marine weather forecasting and warning mission will also be presented and discussed.
Combining TOPEX and SeaWinds Data to Refine Models for Ocean Surface Emissivity: Wind Vector Signatures at 18, 21 and 37 GHz
NASA Technical Reports Server (NTRS)
Vandemark, D.; Tran, N.; Ruf, C.; Vandemark, Douglas (Technical Monitor)
TOPEX Microwave Radiometer (TMR) brightness temperature observations at 18, 21, and 37 GHz have been collocated with near-simultaneous SeaWinds wind vector data as well as with a monthly SST climatological product. The combined data set allows us to study the dependence of ocean surface emissivity (at each frequency) upon both wind speed. Results show clear two-branch wind speed dependence; weak and linear below 6 m/s with an abrupt increase in sensitivity above that point. The analysis also shows that the zenith-directed ocean surface emissivity is polarization dependent above wind speeds of 5-6 m/s with an azimuthal variation related to the wind direction. This last result accords with recent polarimetric radiometer observations collected from aircraft. Implications of these observations to water vapor retrieval algorithms, nadir-viewing polarimetry, and ocean emission modeling will be discussed.
Changes in the T -wave vector loop of the three-dimensional vectorcardiogram during exposure to cold pressor stress
John P. Hatch; Steve Borcherding
Three-dimensional vectorcardiography was used to characterize changes in the T-wave vector loop during exposure to cold pressor stress. Data were collected from 8 subjects during baseline, cold pressor, and recovery periods. Maximum vector length, polar angle of the longest vector, azimuth angle of the longest vector, sum of all vectors, polar angle of the vector sum, azimuth angle of the
Evaluation of ASCAT Ocean Surface Vector Wind (OSVW) Retrievals at NOAA OPC
NASA Astrophysics Data System (ADS)
Ahmad, K. A.; Sienkiewicz, J. M.
The National Oceanic and Atmospheric Administration (NOAA) Ocean Prediction Center (OPC) is responsible for issuing marine weather forecasts and wind warnings over the North Atlantic and North Pacific high seas from 35 degrees West to 160 degrees East, including the offshore waters of the continental United States. In providing accurate marine warnings and forecasts, one of the most significant challenges facing an OPC forecaster is the scarcity of data over the vast ocean regions within the OPC's area of responsibility (AOR). The high quality, remotely sensed ocean surface vector wind (OSVW) data greatly help fill in the immense data void between the sparse conventional surface observations within the OPC's AOR. The SeaWinds scatterometer onboard QuikSCAT satellite has been providing the OPC forecasters, and the operational weather community with near real time (NRT) OSVW data since the spring of 2000. Over the eight years of availability, QuikSCAT winds have become an integral data source in OPC daily operations. An additional source of OSVW data has become available in the large and mostly void regions within the OPC's AOR after the recent launch of the Advanced Scatterometer (ASCAT) in October 2006 by EUMETSAT. The OSVW retrievals from ASCAT are produced at two horizontal resolutions of 50 and 25 km by NOAA NESDIS, and have been available to OPC forecasters since June 2007 and October 2007, respectively. The ASCAT wind data is being routinely viewed by OPC forecasters on a daily basis during the course of their operational shifts. Compared to QuikSCAT, the ASCAT instrument has different capabilities, due to ASCAT's coarser resolution, narrower swath, and reduced sensitivity to rain and high wind speeds. In this paper we provide an overview of the ASCAT measurement characteristics, and the instrument spatial / temporal coverage. Further, we present an up to date assessment of the ASCAT retrievals in support of OPC's analysis and warning operations, where we focus on the utility of the ASCAT OSVW data in detecting Hurricane Force (HF) extratropical cyclones, and estimating the wind warning category. In this activity, we utilize the surface analysis charts prepared by the OPC forecasters to locate and track all HF extratropical cyclones observed over both the North Atlantic and North Pacific oceans during the period from Oct'07 ~ May'08 of the last winter season. Hundreds of passes from ASCAT and QuikSCAT are examined, and wind retrievals are compared to the output of two Numerical Weather Prediction (NWP) models, and where available, to conventional buoy / ship observations. Results indicate that ASCAT can reliably retrieve low to moderate surface wind speeds in all weather conditions. This performance represents an improvement over QuikSCAT, which suffers from an artificially rain inflated retrievals in areas of rain. However, for higher wind speeds, ASCAT retrievals are found to have a low wind speed bias, which degrades the ASCAT capability in detecting extratropical cyclones with Hurricane Force conditions.
Impact of Short Interval SMS Digital Data on Wind Vector Determination for a Severe Local Storms Area
NASA Technical Reports Server (NTRS)
Peslen, C. A.
The impact of 5 minute interval SMS-2 visible digital image data in analyzing severe local storms is examined using wind vectors derived from cloud tracking on time lapsed sequence of geosynchronous satellite images. The cloud tracking areas are located in the Central Plains, where on 6 May 1975, hail-producing thunderstorms occurred ahead of a well defined dry line. The results demonstrate that satellite-derived wind vectors and their associated divergence fields complement conventional meteorological analyses in describing the conditions preceding severe local storm development.
ERIC Educational Resources Information Center
International Association of Business Communicators, San Francisco, CA.
Drawn from a conference focusing on the changing nature of the communication function, the papers in this collection analyze and outline the professional and personal developmental techniques necessary to anticipate and capitalize upon those changes. Among the specific topics discussed in the 32 papers are the following: (1) the techniques and�
Genomic Changes of Chagas Disease Vector, South America
Dujardin, Jean Pierre; Nicolini, Paula; Caraccio, Mar�a Noel; Rose, Virginia; Tellez, Tatiana; Berm�dez, Hern�n; Bargues, Mar�a Dolores; Mas-Coma, Santiago; O�Connor, Jos� Enrique; P�rez, Ruben
We analyzed the main karyologic changes that have occurred during the dispersion of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4�7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. PMID:15109410
Calibration Performance and Capabilities of the New Compact Ocean Wind Vector Radiometer System
NASA Astrophysics Data System (ADS)
Brown, S. T.; Focardi, P.; Kitiyakara, A.; Maiwald, F.; Montes, O.; Padmanabhan, S.; Redick, R.; Russell, D.; Wincentsen, J.
The paper describes performance and capabilities of a new satellite conically imaging microwave radiometer system, the Compact Ocean Wind Vector Radiometer (COWVR), being built by the Jet Propulsion Laboratory (JPL) for an Air Force demonstration mission. COWVR is an 18-34 GHz fully polarimetric radiometer designed to provide measurements of ocean vector winds with an accuracy that meets or exceeds that provided by WindSat, but using a simpler design which has both calibration and cost advantages. Heritage conical radiometer systems, such as WindSat, AMSR, GMI or SSMI(S), all have a similar overall architecture and have exhibited significant intra-channel and inter-sensor calibration biases, due in part to the relative independence of the radiometers between the different polarizations and frequencies in the system. The COWVR system uses a broadband compact hybrid combining architecture and Electronic Polarization Basis Rotation to minimize the number of free calibration parameters between polarization and frequencies, as well as providing a definitive calibration reference from the modulation of the mean polarized signal from the Earth. This second calibration advantage arises because the sensor modulates the incoming polarized signal at the input antenna aperture in a known way based only on the instrument geometry which forces relative calibration consistency between the polarimetric channels of the sensor and provides a gain and offset calibration independent of a model or other ancillary data source, which has typically been a weakness in the calibration and inter-calibration of heritage microwave sensors. This paper will give a description of the COWVR instrument and an overview of the technology demonstration mission. We will discuss the overall calibration approach for this system, its advantages over existing systems and how many of the calibration issues that impact existing satellite radiometers can be eliminated in future operational systems based on this design. COWVR is currently in flight fabrication at JPL, having successfully passed its Critical Design Review in June 2014, and will be flight ready in September 2015 with launch no earlier than 2016.
NSDL National Science Digital Library
Stern, David P. (David Peter), 1931-
This web page, authored and curated by David P. Stern, introduces vectors as an extension of numbers having both magnitude and direction. The initial motivation is to describe velocity but the material includes a general discussion of vector algebra and an application to forces for the inclined plane. The page contains links to a related lesson plan and further opportunities to explore vectors. This is part of the extensive web site "From Stargazers to Starships", that uses space exploration and space science to introduce topics in physics and astronomy. Translations in Spanish and French are available.
Methods of Recording Rapid Wind Changes
NASA Technical Reports Server (NTRS)
Magnan, A
The purpose of our research was to determine the rapid changes of air currents which impose varying stresses on the wings of airplanes. We attempted to express in figures the turbulence of the air, which perhaps plays some role in the behavior of airplanes in flight, as well as in the realization of certain methods of gliding flight. This is the reason which led us to conceive and develop the experimental equipment (hot-wire anemometer) described herein.
Wind farms and weather: the predictability of wind farm-induced changes in the downstream atmosphere.
NASA Astrophysics Data System (ADS)
Barrie, D.; Kirk-Davidoff, D.
The installed wind power capacity worldwide has now exceeded 80 Gigawatts, 12 Gigawatts of which is located in the United States. The size of this capacity is growing at an accelerating rate due to an increasingly reasonable delivery price compared to other energy sources, and improvements in turbine technologies. In light of this growth, we have studied the potential impact that deliberate management of a large wind farm has on both regional climatology and the ability to modify a particular storm's strength and track. We illuminate the extent to which any such changes can be made predictably within a reasonable forecast timeframe. We also distinguish remote anomalies arising from spectral wave generation within the model during the first few time steps from significant anomalies caused by gravity wave propagation away from the wind farm site. Management of a wind farm would be performed in the field by altering the farm's effective roughness length through adjustment of the attitude of the turbine blades with respect to the wind direction. We will also present results that elucidate the dependence of a storm's downstream strength upon both the timing and magnitude of the surface roughness change. This project follows work by Kirk- Davidoff and Keith (2007) that demonstrated a significant extended regional effect on climatology through an alteration of surface roughness over a large area.
Method for changing removable bearing for a wind turbine generator
Bagepalli, Bharat Sampathkumaran (Niskayuna, NY); Jansen, Patrick Lee (Scotia, NY); Gadre, Aniruddha Dattatraya (Rexford, NY)
A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.
Retrieval and Evaluation of Wind Vectors and Advective Surface Velocities from Synthetic Aperture Radar and Infrared Radiometer Data
NASA Astrophysics Data System (ADS)
Carvajal, Gisela; Eriksson, Leif E. B.
Analysis of ocean surface dynamics has been proven to be of vital importance in many areas (e.g. shipping, fishing). Two important parameters to describe the ocean dynamics are the wind velocity (speed and direction) and advective surface velocities (ocean current velocity). These parameters are currently provided operationally by forecast models, surface sensors (e.g. buoys, coastal radar) and satellite sensors. However, coverage limitations, low resolution and limited temporal availability impose a need for implementation and evaluation of new data sources and techniques for estimation of these parameters. In this paper we implement and evaluate known techniques for determination of wind and ocean current velocity from satellite data. Wind is determined from Synthetic Aperture Radar (SAR) data by applying two algo-rithms. First, the Local Gradient method is implemented to extract wind direction from the SAR data, and then the CMOD-5 Geophysical Model Function of the backscatter is inverted to obtain the wind speed as a function of the wind direction and the incidence angle. Current propagation is estimated by analyzing the Sea Surface Temperature propagation in two consec-utive infrared images of the same area from the Advanced Very High Resolution Radiometer. The evaluation shows a good agreement between estimated wind vectors from SAR and scat-terometer data. Comparison with merged ocean current estimates is addressed. The methods will be implemented in the maritime security service provided by the SECTRONIC project funded by the EU 7th framework program.
Analysis of wind bias change with respect to time at Cape Kennedy, Florida, and Vandenberg AFB, California
NASA Technical Reports Server (NTRS)
Adelfang, S. I.
A statistical analysis is presented of the temporal variability of wind vectors at 1 km altitude intervals from 0 to 27 km altitude after applying a digital filter to the original wind profile data sample.
Effects of Local Anthropogenic Changes on Potential Malaria Vector Anopheles hyrcanus and West Nile Virus Vector Culex modestus, Camargue, France
Pon�on, Nicolas; Balenghien, Thomas; Toty, C�line; Ferr�, Jean Baptiste; Thomas, Cyrille; Dervieux, Alain; L�Ambert, Gr�gory; Schaffner, Francis; Bardin, Olivier
Using historical data, we highlight the consequences of anthropogenic ecosystem modifications on the abundance of mosquitoes implicated as the current most important potential malaria vector, Anopheles hyrcanus, and the most important West Nile virus (WNV) vector, Culex modestus, in the Camargue region, France. From World War II to 1971, populations of these species increased as rice cultivation expanded in the region in a political context that supported agriculture. They then fell, likely because of decreased cultivation and increased pesticide use to control a rice pest. The species increased again after 2000 with the advent of more targeted pest-management strategies, mainly the results of European regulations decisions. An intertwined influence of political context, environmental constraints, technical improvements, and social factors led to changes in mosquito abundance that had potential consequences on malaria and WNV transmission. These findings suggest that anthropogenic changes should not be underestimated in vectorborne disease recrudescence. PMID:18258028
Effects of local anthropogenic changes on potential malaria vector Anopheles hyrcanus and West Nile virus vector Culex modestus, Camargue, France.
Pon�on, Nicolas; Balenghien, Thomas; Toty, C�line; Baptiste Ferr�, Jean; Thomas, Cyrille; Dervieux, Alain; L'ambert, Gr�gory; Schaffner, Francis; Bardin, Olivier; Fontenille, Didier
Using historical data, we highlight the consequences of anthropogenic ecosystem modifications on the abundance of mosquitoes implicated as the current most important potential malaria vector, Anopheles hyrcanus, and the most important West Nile virus (WNV) vector, Culex modestus, in the Camargue region, France. From World War II to 1971, populations of these species increased as rice cultivation expanded in the region in a political context that supported agriculture. They then fell, likely because of decreased cultivation and increased pesticide use to control a rice pest. The species increased again after 2000 with the advent of more targeted pest-management strategies, mainly the results of European regulations decisions. An intertwined influence of political context, environmental constraints, technical improvements, and social factors led to changes in mosquito abundance that had potential consequences on malaria and WNV transmission. These findings suggest that anthropogenic changes should not be underestimated in vectorborne disease recrudescence. PMID:18258028
Climate Change Influences on Global Distributions of Dengue and Chikungunya Virus Vectors
Campbell, Lindsay P.; Luther, Caylor; Moo-Llanes, David; Ramsey, Janine M.; Danis-Lozano, Rogelio; Peterson, A. Townsend
This packet presents raster data files that accompany a manuscript submitted for publication to Philosophical Transactions of the Royal Society, titled �Climate Change Influences on Global Vector Distributions for Dengue and Chikungunya Viruses...
Combining Climatic Projections and Dispersal Ability: A Method for Estimating the Responses of Sandfly Vector Species to Climate Change
Fischer, Dominik; Moeller, Philipp; Thomas, Stephanie M.; Naucke, Torsten J.; Beierkuhnlein, Carl
Background In the Old World, sandfly species of the genus Phlebotomus are known vectors of Leishmania, Bartonella and several viruses. Recent sandfly catches and autochthonous cases of leishmaniasis hint on spreading tendencies of the vectors towards Central Europe. However, studies addressing potential future distribution of sandflies in the light of a changing European climate are missing. Methodology Here, we modelled bioclimatic envelopes using MaxEnt for five species with proven or assumed vector competence for Leishmania infantum, which are either predominantly located in (south-) western (Phlebotomus ariasi, P. mascittii and P. perniciosus) or south-eastern Europe (P. neglectus and P. perfiliewi). The determined bioclimatic envelopes were transferred to two climate change scenarios (A1B and B1) for Central Europe (Austria, Germany and Switzerland) using data of the regional climate model COSMO-CLM. We detected the most likely way of natural dispersal (�least-cost path�) for each species and hence determined the accessibility of potential future climatically suitable habitats by integrating landscape features, projected changes in climatic suitability and wind speed. Results and Relevance Results indicate that the Central European climate will become increasingly suitable especially for those vector species with a current south-western focus of distribution. In general, the highest suitability of Central Europe is projected for all species in the second half of the 21st century, except for P. perfiliewi. Nevertheless, we show that sandflies will hardly be able to occupy their climatically suitable habitats entirely, due to their limited natural dispersal ability. A northward spread of species with south-eastern focus of distribution may be constrained but not completely avoided by the Alps. Our results can be used to install specific monitoring systems to the projected risk zones of potential sandfly establishment. This is urgently needed for adaptation and coping strategies against the emerging spread of sandfly-borne diseases. PMID:22140590
Energy Policy 36 (2008) 2333 Change in public attitudes towards a Cornish wind farm
Energy Policy 36 (2008) 23�33 Viewpoint Change in public attitudes towards a Cornish wind farm to particular wind farm developments from the local population which can result in planning permission being to a wind farm change after an extended period following commissioning. Residents of St. Newlyn East
About the correlation between solar micro bursts and the change of the solar wind parameters
Juan Carlos Martinez Oliveros; Daniel Ricardo Izquierdo P
The Sun is the closest star to our planet and it is the most studied, perhaps, there exist too much procesess not-understood. One of the solar processes that have a direct interaction with the earth is the solar wind. The solar wind is defined as the plasma expulsed from the solar atmosphere, this wind was cataloged and is considered that have three components: - Passive solar wind: Is the constant component of the solar wind. - Supersonic and quasistady flux. - Sporadic supersonic flux. We present and brief explanation of the Parker's model of the solar wind and a correlation analysis between solar micro radio bursts and the change of the solar wind parameters.
Characteristics of Wind Velocity and Temperature Change Near an Escarpment-Shaped Road Embankment
Kim, Young-Moon; You, Ki-Pyo; You, Jang-Youl
Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature) due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small. PMID:25136681
Characteristics of wind velocity and temperature change near an escarpment-shaped road embankment.
Kim, Young-Moon; You, Ki-Pyo; You, Jang-Youl
Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature) due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small. PMID:25136681
RNA-seq analyses of blood-induced changes in gene expression in the mosquito vector species, Aedes aegypti
Mariangela Bonizzoni; W Augustine Dunn; Corey L Campbell; Ken E Olson; Michelle T Dimon; Osvaldo Marinotti; Anthony A James
BACKGROUND: Hematophagy is a common trait of insect vectors of disease. Extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. Studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. The mosquito Aedes aegypti (Diptera, Culicidae), a vector of Dengue
Impact to Space Shuttle Vehicle Trajectory on Day of Launch from change in Low Frequency Winds
NASA Technical Reports Server (NTRS)
Decker, Ryan K.; Puperi, Daniel; Leach, Richard
The National Aeronautics and Space Administration's (NASA) Space Shuttle utilizes atmospheric winds on day of launch to develop throttle and steering commands to best optimize vehicle performance while keeping structural loading on the vehicle within limits. The steering commands and resultant trajectory are influenced by both the high and low frequency component of the wind. However, the low frequency component has a greater effect on the ascent design. Change in the low frequency wind content from the time of trajectory design until launch can induce excessive loading on the vehicle. Wind change limits have been derived to protect from launching in an environment where these temporal changes occur. Process of developing wind change limits are discussed followed by an observational study of temporal wind change in low frequency wind profiles at the NASA's Kennedy Space Center area are presented.
Polarization changes in vector Gaussian-Schell-model beams propagating through a thin lens
Liuzhan Pan; Baida Lu
Based on Wolf's general tensorial theory of coherence, in which the vector nature of electromagnetic fields is considered, the closed-form propagation equation of vector Gaussian-Schell-model (GSM) beams passing through a paraxial optical ABCD system is derived, which shows the general applicable advantage, and is used to study polarization changes of GSM beams in passage through a thin lens. It is
Magnetotail Changes in Relation to the Solar Wind Magnetic Field and Magnetospheric Substorms
MICHEL P. AUBRYAND; Robert L. McPherron
Substorm activity is known to be associated with changes in the solar wind parameters and the magnetotail configuration. In this paper we investigate whether the magnetotail changes occur only as a consequence of substorms or also as a direct consequence of changes in the solar wind paxameters. Using data from several satellites (Ogo 5, ATS 1, Imp 4, Explorer 33
Computation of Wind Vectors over the Ocean Using Spaceborne Synthetic Aperture Radar
Jochen Horstmann; Susanne Lehner; Wolfgang Koch; Rasmus Tonboe
he high resolution and large coverage of satellite synthetic aperture radar (SAR) offer a unique opportunity to derive mesoscale wind fields over the ocean surface and to investigate their spatial variation. For this purpose, different algorithms were developed and tested using SAR images from two European Remote Sensing satellites. In this article, the methods for deriving wind fields from SAR
Impacts of past and future climate change on wind energy resources in the United States
NASA Astrophysics Data System (ADS)
McCaa, J. R.; Wood, A.; Eichelberger, S.; Westrick, K.
The links between climate change and trends in wind energy resources have important potential implications for the wind energy industry, and have received significant attention in recent studies. We have conducted two studies that provide insights into the potential for climate change to affect future wind power production. In one experiment, we projected changes in power capacity for a hypothetical wind farm located near Kennewick, Washington, due to greenhouse gas-induced climate change, estimated using a set of regional climate model simulations. Our results show that the annual wind farm power capacity is projected to decrease 1.3% by 2050. In a wider study focusing on wind speed instead of power, we analyzed projected changes in wind speed from 14 different climate simulations that were performed in support of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). Our results show that the predicted ensemble mean changes in annual mean wind speeds are expected to be modest. However, seasonal changes and changes predicted by individual models are large enough to affect the profitability of existing and future wind projects. The majority of the model simulations reveal that near-surface wind speed values are expected to shift poleward in response to the IPCC A2 emission scenario, particularly during the winter season. In the United States, most models agree that the mean annual wind speed values will increase in a region extending from the Great Lakes southward across the Midwest and into Texas. Decreased values, though, are predicted across most of the western United States. However, these predicted changes have a strong seasonal dependence, with wind speed increases over most of the United States during the winter and decreases over the northern United States during the summer.
Polarimetric Ku-Band Scatterometer for High Accuracy, Large Swath Global Wind Vector Measurements
NASA Technical Reports Server (NTRS)
Tsai, Wu-Yang; Nghiem, Son V.; Huddleston, James; Spencer, Michael; Stiles, Bryan; West, Richard
In the past, wind measurements from space using fan-beam antennas, such as Seasat Scatterometer (SASS-1), ERS-1 &2, and NASA scatterometer (NSCAT), required up to six large stick-like antennas and suffered a nadir gap of up to 400 km. In the near future, a spinning pencil-beam scatterometer system is to be used for the SeaWinds scatterometer on QuikSCAT (QSCAT) and on ADEOS-2 (SeaWinds). This scatterometer, though offering wind measurements in the nadir region, still suffers from degraded performance in the nadir and outer swath. The purpose of this paper is to present an advanced polarimetric spinning pencil-beam scatterometer system, which can significantly improve the wind performance across the entire swath. The polarimetric scatterometer simultaneously measures co-polarized backscatter and the polarimetric correlation of co- and cross-polarized radar returns from the ocean surface. The advantage over the conventional scatterometer system is that, while the co-polarization radar returns are even function of the wind direction, the polarimetric correlation is an odd function of wind direction due to the reflection symmetry of the wind roughened surface. Therefore, this polarimetric scatterometer system can provide additional, equivalent measurements at azimuth angle 45degree away from the corresponding co-polarization measurements. The combined co-polarization and correlation measurements enable good wind performance across the whole swath to be obtained. In this paper, we will first present the theoretical formulation of all of the key components required for designing a polarimetric scatterometer. Then, we show that good wind performance can be achieved by a slight improvement in the signal-to-noise ratio of the current QSCAT/SeaWinds design. We then present the predicated wind performance using computer simulation based on a model function for the co-polarized backscatter obtained from actual spaceborne scatterometer data and an estimated model function for the polarimetric correlation based on the asymmetry observed in backscatter data. Finally, we will show that, aside from ocean applications, this polarimetric scatterometer can also be used for ice and land applications.
Postglacial changes of the Southern Hemispheric Westerly Wind belt
NASA Astrophysics Data System (ADS)
Kilian, R.; Lamy, F.; Arz, H.; Kaiser, J.; Baeza, O.; Steinke, T.
Postglacial changes in the latitudinal pattern and intensity of the Southern Hemispheric Westerly Wind Belt (SHW) are still poorly constrained and discussed controversially. Here we address the postglacial SHW evolution based on new and also published data from the southwest coast of South America between 33 and 54�S. Three marine and one lacustrine sediment core from different sites along the fjord system near the westernmost Strait of Magellanes (53�S) show low accumulation rates of biogenic carbonate and high accumulation of minerogenic and organic terrestrial components between 12 and 8.4 kyr BP. These proxies indicate relatively strong precipitation and related low salinities of superficial coastal water and point to strong winds in this central zone of the SHW during this warmest postglacial period in the early Holocene. At the northern margin of the SHW, marine and lacustrine sediment cores and pollen records from the coastal zone off Chile between 33-40�S suggest reduced precipitation and weak westerlies for this period. Taken together, these data are consistent with a southward displacement of the SHW after the Late Glacial and an intensification in its central sector. Our results are apparently in contrast with recently published pollen records from the eastern flank of the Andes between 51-53�S indicating a westward migration of the forest-steppe transition due to reduced westerly rainfall (Villa-Martinez & Moreno 2007; Mayr et al. 2007). We suggest, however, that this vegetation retreat can be explained by increased foehn-induced drought stress on the lee-side of the Andes due to stronger westerly winds. Between 8.4 and 7.9 kyr BP, the Magellanes cores suggest a sudden and strong weakening of the SHW, which could be related to the pronounced 8.2 kyr cold event in the Northern Hemisphere, associated also with a southward migration of the ITCZ. Between 7.9 and 5.5 kyr BP our southern records indicate again stronger westerlies. After around 5.5 kyr BP and during the Neoglacial, the Magellanes sediment cores and new stalagmite records from this area indicate a weakened, but also much more variable SHW, while at that time pollen records from east of the Andes suggest forest expansion towards the steppe, probably caused by less wind-induced drought stress. At the northern SHW margin, various records document increased rainfall, indicating a general northward displacement of the SHW during the late Holocene. Sediment and stalagmite proxies from the Andes between 50-53�S indicate that the coldest and driest Neoglacial phase occurred between 3.5 to 2.5 kyr BP, while at the same time stronger westerlies are recorded from the northern SHW margin. At around 2 kyr BP and during the Medieval Warm Period stalagmite records indicate relatively strong SHW, while the records at the northern SHW margin indicate less SHW influence. Our comparison of SHW records from the northern margin and the central part of the westerlies show that northward (southward) latitudinal displacements of the margin are coupled to reduced (intensified) westerly activity in the center over southernmost South America. Changes in both regions occurred simultaneously on both orbital (insolation-controlled) and millennial (solar variability?) time-scales.
Sharp changes of solar wind density as a possible sign of magnetic reconnection at current sheets
Olga Khabarova; Georgy Zastenker
Sharp changes of solar wind plasma density (or sharp changes of ion flux -SCIFs) were initially observed near the Earth by Interball-1 spacecraft and then confirmed through analyses of WIND SWE data. Abrupt density increases and decreases (in several times per several minutes or even seconds) happen, on the average, several times per day, and they are not associated with
Climate Change and Vector Borne Diseases on NASA Langley Research Center
NASA Technical Reports Server (NTRS)
Cole, Stuart K.; DeYoung, Russell J.; Shepanek, Marc A.; Kamel, Ahmed
Increasing global temperature, weather patterns with above average storm intensities, and higher sea levels have been identified as phenomena associated with global climate change. As a causal system, climate change could contribute to vector borne diseases in humans. Vectors of concern originate from the vicinity of Langley Research Center include mosquitos and ticks that transmit disease that originate regionally, nationwide, or from outside the US. Recognizing changing conditions, vector borne diseases propagate under climate change conditions, and understanding the conditions in which they may exist or propagate, presents opportunities for monitoring their progress and mitigating their potential impacts through communication, continued monitoring, and adaptation. Personnel comprise a direct and fundamental support to NASA mission success, continuous and improved understanding of climatic conditions, and the resulting consequence of disease from these conditions, helps to reduce risk in terrestrial space technologies, ground operations, and space research. This research addresses conditions which are attributed to climatic conditions which promote environmental conditions conducive to the increase of disease vectors. This investigation includes evaluation of local mosquito population count and rainfall data for statistical correlation and identification of planning recommendations unique to LaRC, other NASA Centers to assess adaptation approaches, Center-level planning strategies.
Full vector (3-D) inflow simulation in natural and wind farm environments using an expanded version of the SNLWIND (Veers) turbulence code
Kelley, N.D.
We have recently expanded the numerical turbulence simulation (SNLWIND) developed by Veers [1] to include all three components of the turbulent wind vector. We have also configured the code to simulate the characteristics of turbulent wind fields upwind and downwind of a large wind farm, as well as over uniform, flat terrain. Veers`s original method only simulates the longitudinal component of the wind in neutral flow. This paper overviews the development of spectral distribution, spatial coherence, and cross correlation models used to expired the SNLWIND code to include the three components of the turbulent wind over a range of atmospheric stabilities. These models are based on extensive measurements of the turbulence characteristics immediately upwind and downwind of a large wind farm in San Gorgonio Pass, California.
Measurement of the Wind Vector Over Sea by an Airborne Radar Altimeter Using an Antenna Characterized by Different Beamwidth in the Vertical and Horizontal Planes
Alexey Nekrasov
In this letter, a possibility of recovering the wind vector over sea using an airborne radar altimeter in a short-pulse scatterometer mode is discussed. The nadir-looking wide-beam antenna, with the modified beam shape forming an ellipse footprint, is assumed for the purpose of analysis. Simultaneous range Doppler discrimination techniques are also used and a measuring algorithm of the sea-surface wind
Measurement of the Wind Vector over Sea by an Airborne Radar Altimeter, which has an Antenna with the Ellipse Beam Shape
A. Nekrasov
A possibility of recovering the wind vector over sea using an airborne radar altimeter in a short-pulse scatterometer mode, which has a nadir-looking wide-beam antenna with the modified beam shape forming an ellipse footprint, and in conjunction with simultaneous range Doppler discrimination techniques, is discussed, and a measuring algorithm of the sea surface wind speed and direction is proposed.
Estimating lower winds aloft at Houston, Texas, using a spatial vector regression technique�
Zumwalt, James Tweed
) of the observed Lalte Charles wind. ln atIdition, it appears that the regression equations will yield invalid results when large? wintl-direct. ion differences exist between the two stations; however, analysis of the frcourncy distribution of the IIouston... and LaI-e Charles wind direct. iona indicates that large direction di. fferences occurred only a small percentage of the I. imo. ACKNOW2 EDG21ENTS The anti~or' s gr'aduate program srn sponsored ansi financed by thc United States Air I'orce under...
The impact of climate change on the U.S. wind energy resource
Daniel Kirk-Davidoff; Daniel Barrie
The growing need for low-carbon emitting electricity sources has resulted in rapid growth in the wind power industry. The size and steadiness of the offshore wind resource has attracted growing investment in the planning of offshore wind turbine installations. Decisions about the location and character of wind farms should be made with an eye not only to present but also future wind resource, which may change as increasing carbon dioxide forces reductions in the poleward temperature gradient, and thus potentially in the mean tropospheric westerly winds. I propose to use the new North American Regional Climate Change Assessment Program climate projections to estimate the change of the wind power resource under various carbon dioxide loading scenarios and for a range of climate models. We will compare our assessment with both our assessment based on the IPCC AR4 model runs, to explore the extent to which improved model resolution changes the prediction for the wind power resource, and with present day estimates from reanalysis and scatterometer winds.
Assessment of changes of vector borne diseases with wetland characteristics using multivariate analysis.
Sheela, A M; Sarun, S; Justus, J; Vineetha, P; Sheeja, R V
Vector borne diseases are a threat to human health. Little attention has been paid to the prevention of these diseases. We attempted to identify the significant wetland characteristics associated with the spread of chikungunya, dengue fever and malaria in Kerala, a tropical region of South West India using multivariate analyses (hierarchical cluster analysis, factor analysis and multiple regression). High/medium turbid coastal lagoons and inland water-logged wetlands with aquatic vegetation have significant effect on the incidence of chikungunya while dengue influenced by high turbid coastal beaches and malaria by medium turbid coastal beaches. The high turbidity in water is due to the urban waste discharge namely sewage, sullage and garbage from the densely populated cities and towns. The large extent of wetland is low land area favours the occurrence of vector borne diseases. Hence the provision of pollution control measures at source including soil erosion control measures is vital. The identification of vulnerable zones favouring the vector borne diseases will help the authorities to control pollution especially from urban areas and prevent these vector borne diseases. Future research should cover land use cover changes, climatic factors, seasonal variations in weather and pollution factors favouring the occurrence of vector borne diseases. PMID:25412801
Modified vector control algorithm for increasing partial-load efficiency of fractional-slot concentrated-winding surface PM machines
El-Refaie, Ayman M [ORNL; Jahns, Thomas M [ORNL; Reddy, Patel [University of Wisconsin; McKeever, John W [ORNL
This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface permanent magnet (SPM) machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis for a 55-kW (peak) SPM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by > 6% at 2000 r/min compared to the maximum torque/ampere algorithm, making the machine much more attractive for its intended application.
Modified vector control algorithm for increasing partial-load efficiency of fractional-slot concentrated-winding surface PM machines
El-Refaie, Ayman M [ORNL; Jahns, Thomas M [ORNL; Reddy, Patel [University of Wisconsin; McKeever, John W [ORNL
This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface PM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis (FEA) for a 55 kW (peak) surface PM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by >6% at 2000 rpm compared to the maximum torque/amp algorithm, making the machine much more attractive for its intended application
Multilevel space-vector PWM algorithm for seven-phase open-end winding drives
N. Bodo; M. Jones; E. Levi
Open-end winding variable speed drives with dual- inverter supply have been extensively investigated for various applications in the past, based on a three-phase machine con- figuration. This topology is relatively simple for practical reali- sation. It offers a higher number of switching states without the need for capacitor voltage balancing algorithms, when com- pared to the equivalent standard multi-level converter
NSDL National Science Digital Library
National Energy Education Development (NEED) Project
This document examine wind power as an energy resource. The reading will define wind and discuss topics such as (1) The history of wind machines, (2) Today's windmills, and (3) Types of wind machines. This resource is structured as an informational handout to supplement your energy activities or to generate discussion questions. Copyright 2005 International Technology Education Association
A spatially interactive simulation of climate change, harvesting, wind, and tree species migration and
Mladenoff, David
A spatially interactive simulation of climate change, harvesting, wind, and tree species migration to climate change. Our objective was to estimate the combined effects of climate change, common disturbances) to generate transient growth and decomposition parameters for 23 species. The two climate change scenarios
Global climatology of the wind vector rotation - implications for the orographic gravity waves propagation
NASA Astrophysics Data System (ADS)
Pisoft, Petr; Sacha, Petr; Kuchar, Ales
The gravity waves spectrum is shaped not only by different sources but it also reflects tropospheric background conditions contributing to filtering of various gravity waves. This could be most easily illustrated for the propagation of the orographic gravity waves that are critically filtered when the wind speed is zero. This condition is ensured in case of the directional shear exceeding 180�. Above regions where it is fulfilled, one can rule out the possibility of orographic GW modes contributing to the observed GW activity and vice versa regions of small wind rotation in the lower levels are often precursors of enhanced GW activity higher. In this study, we have performed a global analysis of the background conditions with a focus on the rotation of the ground level winds. We have analyzed MERRA and JRA-55 time series. The results provided climatology of atmospheric regions with the conditions favorable for the upward propagation of the orographic gravity waves from the troposphere into the stratosphere. The regions are detected mainly over areas where tropospheric and stratospheric jets coincide. The study is supplemented by a global analysis of the fields of potential energy of disturbances as a proxy for gravity waves activity using COSMIC GPS RO data.
A Sudden Change in the Solar Wind Pressure and the Outer Region of the Magnetosphere
The motions of the magnetic field lines and of the plasma in the outermost region of the magnetosphere that are caused by a sudden change in the solar wind pressure are studied. Using Mead's model for the initial and the final field configurations of the magnetic field in the magnetosphere, the field line displacements due to a sudden solar wind
Recent near-surface wind changes in the central Mediterranean and Adriatic areas
Paolo Antonio Pirazzoli; Alberto Tomasin
Trends of change in wind direction and velocity during the second part of the last century are examined at 17 coastal Italian stations along a north-south transect over 1000 km long in the central Mediterranean area. Linear regressions and confidence ranges are provided for the frequency and for annual maximum and mean velocities. It appears that wind activity has been
The predicted impact of possible climatic change on virus-vector nematodes in Great Britain
R. Neilson; B. Boag
Data extracted from surveys of plant-parasitic nematodes in Great Britain allowed relatively detailed maps of the geographical distribution of various longidorid and trichodorid virus-vector nematode species to be produced. These distributions are related to long-term monthly mean temperature. Recently published figures for climate change were applied to the distribution data. A potential increase in nematode associated problems due to climate
North Sea wind climate in changing weather regimes
NASA Astrophysics Data System (ADS)
Anders, Ivonne; Rockel, Burkhardt
Results from regional climate models (RCMs) are getting more and more important in future wind climate assessment. From RCMs often only the daily wind speed is available, but no information on prevailing wind direction of each day. Weather regime classification can close this gap and models ability of simulating surface wind speed can be analysed in detail. Several objective regime classifications have been investigated to be a sufficient diagnostic tool to evaluate the present wind climate at the German and Dutch coastal area of the North Sea. The classification by Jenkinson and Collison (1977) uses values for mean sea level pressure at 16 locations centered over the North Sea. Beside the predefined 8 prevailed wind directions and the two possibilities on cyclonic or anticyclonic turbulence, 2x8 hybrid weather types can be defined. In this way 27 different regimes can be distinguished including a class of non-classifiable cases. The 27 regimes could be reduced to a number of 11 by allotting the hybrid types to the directional or the centered types. As the classification is carried out for the North Sea based on ERA40 mean sea level pressure the different regimes clearly reflect the mean wind characteristics at the stations. Comparing the wind roses for the individual observations leads to the assumption that the regime classification described before fits the requirements to carry out the regime dependent evaluation of the RCMs with a focus on the German and Dutch coast. Trends in the occurrence of the regimes in the winter period of 1961 to 2000 show an increase of the regimes with Western and Southwestern wind directions and a decrease of wind events from Eastern directions in the North Sea. The trend is dominated by the strong positive phase of the NAO especially in the months January to March starting in the beginning of the 1980s. Due to the applied method ERA40 and the RCMs do not necessarily show the same regime at each day. The agreement among the RCM simulations carried out in the ENSEMBLES framework and ERA40 has been analysed in a last step. References: Jenkinson A, Collison F (1977) An initial climatology of gales over the north sea. Synoptic Climatology Branch Memorandum 62:18pp, UK Met Office
Modeling and space vector control of a novel multilevel matrix converter for variable-speed wind power generators
NASA Astrophysics Data System (ADS)
Al-Naseem, Osama Abdulrahman
A novel multilevel matrix converter is developed to efficiently transfer energy between a three-phase variable-speed generator of a wind turbine and a three-phase ac utility network. Optimizing the energy transfer efficiency at light load is critical in variable-speed wind generators. Laboratory experiment suggests that converter efficiency at light load may be increased via soft-switching and multilevel switching techniques. The new converter includes the advantages of multilevel converters, such as reduced harmonic content, increased power handling capability without additional switching loss, and high efficiency at low machine voltages. It also features the characteristics of conventional matrix converters, such as space vector control and improved efficiency via auxiliary resonant commutation soft-switching techniques. Similar to a conventional matrix converter, the novel multilevel matrix converter uses a nine-switch matrix with four-quadrant switches to connect input phases at one side of the converter with output phases at the other side of the converter. However, the switches of the new converter are configured differently from those used in the conventional matrix converter. Each switch of the new converter is a cell that resembles a full-bridge inverter topology and can assume three voltage levels while used. Semiconductor devices in a switch cell are always clamped to a known constant do voltage of a capacitor. This is a typical characteristic of multilevel converters where device voltage stresses are reduced by clamping the main transistor voltages to low levels. With reduced voltage stresses, switching frequency can be increased to allow for reduced size of filter magnetics. Unlike conventional matrix converter, the multilevel matrix converter uses inductors on both input and output sides of the converter. This symmetry allows for both step up and step down operations. Each switch cell features double the power handling capability compared to the four-quadrant switches used in a conventional matrix converter. This increase in power handling capability is due to the doubling of the number of devices in a multilevel matrix converter switch cell. Scaling up the power handling capability is accomplished by cascading more than one switch cell per branch. Control of the new converter is achieved through space vector modulation in which three-phase ac voltages are transformed to the d-q reference frame and compared with a set of space vectors prior to modulation. Since it has 19683 different switching combinations, control can be difficult and complex. Nevertheless, the multilevel matrix converter has been modeled and controlled through simulation. Simulation results show the possibility of operating the converter to produce the desired voltage waveforms with universal input and output power factors and maintain constant capacitor voltages simultaneously. Also in this dissertation is the derivation of an analytical averaged equivalent circuit model of a PWM converter. This model reveals how dominant loss mechanisms vary with converter operating point. The model is based on the operational characteristics of power diodes and IGBTs. Laboratory experiments support the derived model and confirm that IGBT current tailing and diode reverse-recovery are indeed the most critical losses in a PWM converter. These losses are more significant at light load, hence reducing the energy capture capability of converters used in wind generation. The results suggest that multilevel conversion, which has been employed in the novel multilevel matrix converter, could improve the low-wind converter efficiency.
Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs
Haak, Hein
Wind extremes in the North Sea Basin under climate change: An ensemble study of 12 CMIP5 GCMs R. C levels and waves are generated by low atmospheric pressure and severe wind speeds during storm events. As a result of the geometry of the North Sea, not only the maximum wind speed is relevant, but also wind
Climate Change, Public Health, and Decision Support: The New Threat of Vector-borne Disease
NASA Astrophysics Data System (ADS)
Grant, F.; Kumar, S.
Climate change and vector-borne diseases constitute a massive threat to human development. It will not be enough to cut emissions of greenhouse gases-the tide of the future has already been established. Climate change and vector-borne diseases are already undermining the world's efforts to reduce extreme poverty. It is in the best interests of the world leaders to think in terms of concerted global actions, but adaptation and mitigation must be accomplished within the context of local community conditions, resources, and needs. Failure to act will continue to consign developed countries to completely avoidable health risks and significant expense. Failure to act will also reduce poorest of the world's population-some 2.6 billion people-to a future of diminished opportunity. Northrop Grumman has taken significant steps forward to develop the tools needed to assess climate change impacts on public health, collect relevant data for decision making, model projections at regional and local levels; and, deliver information and knowledge to local and regional stakeholders. Supporting these tools is an advanced enterprise architecture consisting of high performance computing, GIS visualization, and standards-based architecture. To address current deficiencies in local planning and decision making with respect to regional climate change and its effect on human health, our research is focused on performing a dynamical downscaling with the Weather Research and Forecasting (WRF) model to develop decision aids that translate the regional climate data into actionable information for users. For the present climate WRF was forced with the Max Planck Institute European Center/Hamburg Model version 5 (ECHAM5) General Circulation Model 20th century simulation. For the 21th century climate, we used an ECHAM5 simulation with the Special Report on Emissions (SRES) A1B emissions scenario. WRF was run in nested mode at spatial resolution of 108 km, 36 km and 12 km and 28 vertical levels. This model was examined relative to two mosquito vectors, both competent carriers of dengue fever, a viral, vector-borne disease. Models which incorporate public health considerations can enable decision makers to take proactive steps to mitigate the impacts and adapt to the changing environmental conditions. In this paper we provide a snapshot of our climate initiative and some examples relative to our public health practice work in vector-borne diseases to illustrate how integrated decision support could be of assistance to regional and local communities worldwide.
Sharp solar wind density changes and their connection with heliospheric current sheet
O. V. Khabarova; G. N. Zastenker
Poor-investigated sharp changes of solar wind plasma density (its increases and decreases in several times during several minutes or even seconds), simultaneously observed by Interball-1 and Wind spacecraft near the Earth, on the average, several times per day, are considered. Firstly they had been found due to analysis of Interball-1 one-second plasma data and were called as SCIFs (sharp changes
Operation of a wind turbine-flywheel energy storage system under conditions of stochastic change of wind energy.
Tomczewski, Andrzej
The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author's opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical parameters of a wind turbine-energy storage system and its geographical location one can determine the boundary capacity of the storage, which helps prevent power cuts to the grid at the assumed probability. Flywheel energy storage was selected due to its characteristics and technical parameters. The storage capacity was determined based on an empirical relationship using the results of the proposed statistical and energetic analysis of the measured wind velocity courses. A detailed algorithm of the WT-FESS with the power grid system was developed, eliminating short-term breaks in the turbine operation and periods when the wind turbine power was below the assumed level. PMID:25215326
Risk maps for range expansion of the Lyme disease vector, Ixodes scapularis, in Canada now and with climate change
Nicholas H Ogden; Laurie St-Onge; Ian K Barker; St�phanie Brazeau; Michel Bigras-Poulin; Dominique F Charron; Charles M Francis; Audrey Heagy; L Robbin Lindsay; Abdel Maarouf; Pascal Michel; Fran�ois Milord; Christopher J O'Callaghan; Louise Trudel; R Alex Thompson
BACKGROUND: Lyme disease is the commonest vector-borne zoonosis in the temperate world, and an emerging infectious disease in Canada due to expansion of the geographic range of the tick vector Ixodes scapularis. Studies suggest that climate change will accelerate Lyme disease emergence by enhancing climatic suitability for I. scapularis. Risk maps will help to meet the public health challenge of
Perspective�riding the wind: managing new product development in an age of change
Chuck Tomkovick; Christopher Miller
New product development (NPD) has never been more challenging or rewarding than it is today. With the dawning of the new millennium, new product developers now find themselves in an �age of change,� the likes of which the world has never known. The rate of change is numbing, if not stupefying for many business people. With the winds of change
Effect of sudden solar wind dynamic pressure changes at subauroral latitudes: Change in magnetic field
Le, G.; Russell, C.T.; Petrinec, S.M.; Ginskey, M. (Univ. of California, Los Angeles (United States))
The observations obtained during the International Magnetospheric Study (IMS) from the magnetometers of the IGS network extending from Cambridge, England, to Tromso, Norway, are used to study the response of subauroral current systems to sudden changes in solar wind dynamic pressure. Observations show that the response is very strong at subauroral latitudes. The preliminary response in the H component is a brief, small increase in the dayside moring sector and a decrease in the afternoon and night sectors. The main response in the horizontal field (the H and D components) is toward the pole except in the dayside morning sector. The inferred ionospheric current is mainly a circulatory system flowing counterclockwise when viewed form the north pole everywhere at subauroral latitudes except the dayside morning sector. 29 refs., 12 figs.
Scatterometer Ocean Surface Winds Provide Observational Evidence for Changes in the Hadley Cell
NASA Astrophysics Data System (ADS)
Hristova-Veleva, S. M.; Haddad, Z.; Rodriguez, E.; Stiles, B. W.; Turk, F. J.; Seo, E.
Recent evidence suggests that the tropics have expanded over the last few decades by a very rough 1 degree per decade. This is considered to be an atmospheric response to the observed tropical ocean warming trend (e.g. Quan et al., 2004). If continued, the expansion of the tropics (the Hadley cell) could have a substantial impact on water resources and the ecology of the sub-tropics. Until now, the understanding of the mechanisms that govern the changing width of the tropics has been confined to models and proxies (e.g. Johanson and Fu, 2009; Hu and Fu 2007 (OLR); Lu et al. 2007 (precipitation /evaporation estimates) because of the unavailability of systematic observations of the large-scale circulation. Ocean surface vector winds, derived from scatterometer observations, provide for the first time an accurate depiction of the large-scale circulation and allow the study of the Hadley cell evolution through analysis of its surface branch. The launch of NASA's QuikSCAT in 1999 marked the beginning of routine global observations of the surface winds and provided a consistent 10-year record. The launches of ASCAT on METOP in 2006 and the ISRO's OceanSAT-2 in 2010 will assure the continuation of the climate data record of near-surface winds over the oceans. In this study we use the observations from QuikSCAT. We determine the extent of the Hadley cell as defined by the subtropical zero-crossing of the zonally-averaged zonal wind component (the separation between the midlatitude westerlies and the easterly winds in the tropics). We study the time series of 1-year running averages, 260 in total and offset from each other by two weeks. Our preliminary studies revealed a couple of interesting results: - The first half of the 10-year record shows two distinct cycles in the width of the Hadley cell while the later part of the record shows a steady increase in that width, as has been shown by others. The magnitude of the width-increase is very close to what has been reported by others (~1 deg/decade, both south and north, for a total of about 2 deg/decade). - The two cycles in the 1999-2004 time period are likely a reflection of the modulation of the Hadley cell by the La Nina(1999)/El Nino (2002) events that dominated this period - Segregating the data by ocean basins show rather different evolution of the Pacific Hadley cell versus that in the Atlantic. - Analyzing the time series of 3-month running averages reveals the seasonal variation of the extent and the width of the Hadley cell. It indicates a trend for pole-ward expansion of the northern Hadley cell branch during the boreal winter. This result is consistent with an earlier finding by Quan et al. (2004) that the winter Hadley cell has been increasing in intensity since 1950. Next, we look into a more detailed analysis to relate these preliminary findings to a more in-depth investigation of the relation between the Hadley cell strength and the El Nino/ La Nina episodes. In the future we will relate the scatterometer-defined Hadley cell characteristics and tendencies to such from precipitation observations.
Correlated solar wind speed, density, and magnetic field changes at J. D. Richardson and C. Wang1
Richardson, John
Correlated solar wind speed, density, and magnetic field changes at Voyager 2 J. D. Richardson December 2003. [1] The character of the solar wind plasma data observed by Voyager 2 recently changed of the solar wind. The model reproduces the basic character (but not the details) of the observations
Modelling potential changes in marine biogeochemistry due to large-scale offshore wind farms
NASA Astrophysics Data System (ADS)
van der Molen, Johan; Rees, Jon; Limpenny, Sian
Large-scale renewable energy generation by offshore wind farms may lead to changes in marine ecosystem processes through the following mechanism: 1) wind-energy extraction leads to a reduction in local surface wind speeds; 2) these lead to a reduction in the local wind wave height; 3) as a consequence there's a reduction in SPM resuspension and concentrations; 4) this results in an improvement in under-water light regime, which 5) may lead to increased primary production, which subsequently 6) cascades through the ecosystem. A three-dimensional coupled hydrodynamics-biogeochemistry model (GETM_ERSEM) was used to investigate this process for a hypothetical wind farm in the central North Sea, by running a reference scenario and a scenario with a 10% reduction (as was found in a case study of a small farm in Danish waters) in surface wind velocities in the area of the wind farm. The ERSEM model included both pelagic and benthic processes. The results showed that, within the farm area, the physical mechanisms were as expected, but with variations in the magnitude of the response depending on the ecosystem variable or exchange rate between two ecosystem variables (3-28%, depending on variable/rate). Benthic variables tended to be more sensitive to the changes than pelagic variables. Reduced, but noticeable changes also occurred for some variables in a region of up to two farm diameters surrounding the wind farm. An additional model run in which the 10% reduction in surface wind speed was applied only for wind speeds below the generally used threshold of 25 m/s for operational shut-down showed only minor differences from the run in which all wind speeds were reduced. These first results indicate that there is potential for measurable effects of large-scale offshore wind farms on the marine ecosystem, mainly within the farm but for some variables up to two farm diameters away. However, the wave and SPM parameterisations currently used in the model are crude and need to be further tested and refined. Also, potential counter-acting processes such as possible increases in SPM concentrations due to turbulence generated by the wind-turbine foundations may need to be included for more accurate simulations. Moreover, it is unclear to what extent these results would be valid for areas where different hydrodynamic characteristics may predominate, e.g. with summer stratification or strong tidal currents. Finally, an assessment would need to be carried out of how beneficial or detrimental these potential changes might be from various social-economic and ecosystem-management points of view.
Dynamics of Sylvatic Chagas Disease Vectors in Coastal Ecuador Is Driven by Changes in Land Cover
Grijalva, Mario J.; Ter�n, David; Dangles, Olivier
Background Chagas disease is a serious public health problem in Latin America where about ten million individuals show Trypanosoma cruzi infection. Despite significant success in controlling domiciliated triatomines, sylvatic populations frequently infest houses after insecticide treatment which hampers long term control prospects in vast geographical areas where vectorial transmission is endemic. As a key issue, the spatio-temporal dynamics of sylvatic populations is likely influenced by landscape yet evidence showing this effect is rare. The aim of this work is to examine the role of land cover changes in sylvatic triatomine ecology, based on an exhaustive field survey of pathogens, vectors, hosts, and microhabitat characteristics' dynamics. Methodology and Principal Findings The study was performed in agricultural landscapes of coastal Ecuador as a study model. Over one year, a spatially-randomized sampling design (490 collection points) allowed quantifying triatomine densities in natural, cultivated and domestic habitats. We also assessed infection of the bugs with trypanosomes, documented their microhabitats and potential hosts, and recorded changes in landscape characteristics. In total we collected 886 individuals, mainly represented by nymphal stages of one triatomine species Rhodnius ecuadoriensis. As main results, we found that 1) sylvatic triatomines had very high T. cruzi infection rates (71%) and 2) densities of T. cruzi-infected sylvatic triatomines varied predictably over time due to changes in land cover and occurrence of associated rodent hosts. Conclusion We propose a framework for identifying the factors affecting the yearly distribution of sylvatic T. cruzi vectors. Beyond providing key basic information for the control of human habitat colonization by sylvatic vector populations, our framework highlights the importance of both environmental and sociological factors in shaping the spatio-temporal population dynamics of triatomines. A better understanding of the dynamics of such socio-ecological systems is a crucial, yet poorly considered, issue for the long-term control of Chagas disease. PMID:24968118
Changes in the Burgers Vector of Perfect Dislocation Loops without Contact with the External Dislocations
Arakawa, K.; Hatanaka, M.; Mori, H. [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, 7-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kuramoto, E. [Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Ono, K. [Department of Material Science, Shimane University, 1060 Nishikawatsu, Matsue 690-8504 (Japan)
We report the observations of a new type of changing process in the Burgers vector of dislocations by in situ transmission electron microscopy. Small interstitial-type perfect dislocation loops in bcc iron with diameters less than approximately 50 nm are transformed from a 1/2<111> loop to another 1/2<111> one or an energetically unfavorable <100> one; furthermore, a <100> loop is transformed to a 1/2<111> one. These transformations occurred on high-energy electron irradiation or simple heating without contact with external dislocations. The origin of these phenomena is discussed.
Effect of change in large and fast solar wind dynamic pressure on geosynchronous magnetic field
NASA Astrophysics Data System (ADS)
N, Borodkova L.; Liu, Jing-Bo; Huang, Zhao-Hui; G, Zastenker N.; Wang, Chi; P, Eiges E.
We present a comparison of changes in large and sharp solar wind dynamic pressure, observed by several spacecraft, with fast disturbances in the magnetospheric magnetic field, measured by the geosynchronous satellites. More than 260 changes in solar wind pressure during the period 1996-2003 are selected for this study. Large statistics show that an increase (a decrease) in dynamic pressure always results in an increase (a decrease) in the magnitude of geosynchronous magnetic field. The amplitude of response to the geomagnetic field strongly depends on the location of observer relative to the noon meridian, the value of pressure before disturbance, and the change in amplitude of pressure.
Features of ocean microwave emission changed by wind at 6 GHz
Akira Shibata
Ocean microwave emissions changed by the ocean wind at 6 GHz were investigated by combining data of the Advanced Microwave\\u000a Scanning Radiometer (AMSR) and SeaWinds, both aboard the Advanced Earth Observation Satellite-II (ADEOS-II). This study was\\u000a undertaken to improve the accuracy of the sea surface temperature (SST) retrieved from the AMSR 6 GHz data. Two quantities,\\u000a 6V*(H*), were defined by
Environmental change and water-related, vector borne diseases in eastern Africa: the HEALTHY FUTURES project
NASA Astrophysics Data System (ADS)
Taylor, David; Kienberger, Stefan; Tompkins, Adrian
Pathogens that spend time outside the human body, and any organisms involved in their transmission, have particular ecological requirements; as environment, including climate, conditions change, then the transmission characteristics of associated pathogens - and the diseases caused - are also likely to vary. Relationships between environment and health in many parts of the world remain poorly studied and are often overlooked, however. This is particularly the case in developing countries, because of budgetary and available expertise constraints. Moreover the relationship is often confounded by other factors. These other factors contribute to human vulnerability, and thus to the overall disease risk due to environmental change. This presentation will highlight the importance of environmental, including climate, change information to a better understanding of the risks to health of projected future environmental changes, and to the more efficient and effective use of scarce health resources in the developing world. The paper will focus on eastern Africa, and in particular the health effects of future projected environmental change impacts on water-related, vector borne diseases in the East African Community region. Moreover the paper will highlight how the EU FP7-funded project HEALTHY FUTURES is, through a broadly-based, integrative approach that distinguishes environmental change-induced health hazard from health risk aims to support the health decisions making process, thereby attempting to help mitigate negative health impacts.
Climate, Environmental, and Socioeconomic Change Weighing up the Balance in Vector-Borne Disease Transmission
Parham, Paul [University of Liverpool; Waldock, Johanna [Imperial College, London; Christophides, George [Imperial College, London; Hemming, Deborah [Met Office Hadley Centre, UK; Agusto, Folashade [Austin Peay State University; Evans, Katherine J [ORNL; Fefferman, Nina [Rutgers University; Gaff, Holly [Old Dominion University; Gumel, Abba [Arizona State University; LaDeau, Shannon [The University of Tennessee; Lenhart, Suzanne [University of Tennessee, Knoxville (UTK); Mickens, Ronald [Clark Atlanta University; Naumova, Elena [Tufts University; Ostfeld, Richard [Cary Institute of Ecosystem Studies, New York; Ready, Paul [Natural History Museum; Thomas, Matthew [Pennsylvania State University; Velasco-Hernandez, Jorge [Universidad Nacional Autonoma de Mexico (UNAM); Edwin, Michael [University of Notre Dame, IN
Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is due not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but, perhaps most crucially, the multitude of epidemiological, ecological, and socioeconomic factors that drive VBD transmission, and this complexity has generated considerable debate over the last 10-15 years. In this article, and Theme Issue, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions, and, crucially, offer some solutions for the field moving forwards. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems. This Theme Issue seeks to cover both, reflected in the breadth and depth of the topics and VBD-systems considered, itself strongly indicative of the challenging, but necessary, multidisciplinary nature of this research field.
Study of light-induced vector changes in the local atomic structure of AsSe glasses by EXAFS
Drabold, David
Study of light-induced vector changes in the local atomic structure of As�Se glasses by EXAFS G changes in the local structure of As�Se glasses using extended X-ray ab- sorption fine structure (EXAFS) by extended X-ray absorption fine structure (EXAFS) analysis around Se as well as As atoms in AsxSe1�x films
Integrated data processing of remotely sensed and vector data for building change detection
NASA Astrophysics Data System (ADS)
Sofina, N.; Ehlers, M.; Michel, U.
In recent years natural disasters have had an increasing impact leading to tremendous economic and human losses. Remote sensing technologies are being used more often for rapid detection and visualization of changes in the affected areas, providing essential information for damage assessment, planning and coordination of recovery activities. This study presents a GIS-based approach for the detection of damaged buildings. The methodology is based on the integrated analysis of vector data containing information about the original urban layout and remotely sensed images obtained after a catastrophic event. For the classification of building integrity a new `Detected Part of Contour' (DPC) feature was developed. The DPC feature defines a part of the building contour that can be detected in the related remotely sensed image. It reaches maximum value (100%) if the investigated building contour is intact. Next, several features based on the analysis of textural information of the remotely sensed image are considered. Finally, a binary classification of building conditions concludes the change detection analysis. The proposed method was applied to the 2010 earthquake in Qinghai (China). The results indicate that a GIS-based analysis can markedly improve the accuracy of change detection analysis. The proposed methodology has been developed solely within the Open Source Software environment (GRASS GIS, Python, Orange). The employment of Open Source Software provides the way for an innovative, flexible and costeffective implementation of change detection operations.
Estimated Effects of Projected Climate Change on the Basic Reproductive Number of the Lyme Disease Vector Ixodes scapularis
Radojevic�, Milka; Wu, Xiaotian; Duvvuri, Venkata R.; Leighton, Patrick A.; Wu, Jianhong
Background: The extent to which climate change may affect human health by increasing risk from vector-borne diseases has been under considerable debate. Objectives: We quantified potential effects of future climate change on the basic reproduction number (R0) of the tick vector of Lyme disease, Ixodes scapularis, and explored their importance for Lyme disease risk, and for vector-borne diseases in general. Methods: We applied observed temperature data for North America and projected temperatures using regional climate models to drive an I. scapularis population model to hindcast recent, and project future, effects of climate warming on R0. Modeled R0 increases were compared with R0 ranges for pathogens and parasites associated with variations in key ecological and epidemiological factors (obtained by literature review) to assess their epidemiological importance. Results: R0 for I. scapularis in North America increased during the years 1971�2010 in spatio-temporal patterns consistent with observations. Increased temperatures due to projected climate change increased R0 by factors (2�5 times in Canada and 1.5�2 times in the United States), comparable to observed ranges of R0 for pathogens and parasites due to variations in strains, geographic locations, epidemics, host and vector densities, and control efforts. Conclusions: Climate warming may have co-driven the emergence of Lyme disease in northeastern North America, and in the future may drive substantial disease spread into new geographic regions and increase tick-borne disease risk where climate is currently suitable. Our findings highlight the potential for climate change to have profound effects on vectors and vector-borne diseases, and the need to refocus efforts to understand these effects. Citation: Ogden NH, Radojevi? M, Wu X, Duvvuri VR, Leighton PA, Wu J. 2014. Estimated effects of projected climate change on the basic reproductive number of the Lyme disease vector Ixodes scapularis. Environ Health Perspect 122:631�638;?http://dx.doi.org/10.1289/ehp.1307799 PMID:24627295
An Ill Wind? Climate Change, Migration, and Health
Barnett, Jon
Background: Climate change is projected to cause substantial increases in population movement in coming decades. Previous research has considered the likely causal influences and magnitude of such movements and the risks to national and international security. There has been little research on the consequences of climate-related migration and the health of people who move. Objectives: In this review, we explore the role that health impacts of climate change may play in population movements and then examine the health implications of three types of movements likely to be induced by climate change: forcible displacement by climate impacts, resettlement schemes, and migration as an adaptive response. Methods: This risk assessment draws on research into the health of refugees, migrants, and people in resettlement schemes as analogs of the likely health consequences of climate-related migration. Some account is taken of the possible modulation of those health risks by climate change. Discussion: Climate-change�related migration is likely to result in adverse health outcomes, both for displaced and for host populations, particularly in situations of forced migration. However, where migration and other mobility are used as adaptive strategies, health risks are likely to be minimized, and in some cases there will be health gains. Conclusions: Purposeful and timely policy interventions can facilitate the mobility of people, enhance well-being, and maximize social and economic development in both places of origin and places of destination. Nevertheless, the anticipated occurrence of substantial relocation of groups and communities will underscore the fundamental seriousness of human-induced climate change. PMID:22266739
Understanding the change in the coastal and oceanic winds off Peru at seasonal to interdecadal timescales.
Understanding the change in the coastal and oceanic winds off Peru at seasonal to interdecadal,2) , Carlos Ruiz(1) and Carlos Quispe(1) (1)Instituto del Mar del Peru. Esquina Gamarra y Valle S/N.Callao-Peru to the equatorial dynamics, the upwelling off Peru is influenced by climate variability at a variety of timescales
The magnetohydrodynamic response of the magnetospheric cavity to changes in solar wind pressure
David J. Southwood; Margaret G. Kivelson
The magnetohydrodynamic excitation of a cold magnetized plasma in a cavity by externally imposed pressure perturbations is examined through use of various simple models. The purpose is to outline the possible responses triggered in the terrestrial magnetosphere by the changes in the solar wind dynamic pressure or other sources of pressure perturbation at the magnetopause. Although the source is compressional,
Climate Change, Vector-borne Disease and Interdisciplinary Research: Social Science Perspectives on an Environment and Health Controversy
Ben W. Brisbois; S. Harris Ali
Over the last two decades, the science of climate change�s theoretical impacts on vector-borne disease has generated controversy\\u000a related to its methodological validity and relevance to disease control policy. Critical social science analysis, drawing\\u000a on science and technology studies and the sociology of social movements, demonstrates consistency between this controversy\\u000a and the theory that climate change is serving as a
Titan's rotation reveals an internal ocean and changing zonal winds.
Lorenz, Ralph D; Stiles, Bryan W; Kirk, Randolph L; Allison, Michael D; Del Marmo, Paolo Persi; Iess, Luciano; Lunine, Jonathan I; Ostro, Steven J; Hensley, Scott
Cassini radar observations of Saturn's moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of approximately 0.36 degrees per year in apparent longitude and is consistent with seasonal exchange of angular momentum between the surface and Titan's dense superrotating atmosphere, but only if Titan's crust is decoupled from the core by an internal water ocean like that on Europa. PMID:18356521
Calcium mobilizations in response to changes in the gravity vector in Arabidopsis seedlings
Tatsumi, Hitoshi; Toyota, Masatsugu; Furuichi, Takuya; Sokabe, Masahiro
Gravity influences the growth direction of higher plants. Changes in the gravity vector (gravistimulation) immediately promote the increase in the cytoplasmic free calcium ion concentration ([Ca2+]c) in Arabidopsis (Arabidopsis thaliana) seedlings. When the seedlings are gravistimulated by reorientation at 180�, a transient two peaked (biphasic) [Ca2+]c-increase arises in their hypocotyl and petioles. Parabolic flights (PFs) can generate a variety of gravity-stimuli, and enables us to measure gravity-induced [Ca2+]c-increases without specimen rotation, which demonstrate that Arabidopsis seedlings possess a rapid gravity-sensing mechanism linearly transducing a wide range of gravitational changes into Ca2+ signals on a sub-second timescale. Hypergravity by centrifugation (20 g or 300 g) also induces similar transient [Ca2+]c-increases. In this review, we propose models for possible cellular processes of the garavi-stimulus-induced [Ca2+]c-increase, and evaluate those by examining whether the model fits well with the kinetic parameters derived from the [Ca2+]c-increases obtained by applying gravistimulus with different amplitudes and time sequences. PMID:25763612
Zoom in at African country level: potential climate induced changes in areas of suitability for survival of malaria vectors
Background Predicting anopheles vectors� population densities and boundary shifts is crucial in preparing for malaria risks and unanticipated outbreaks. Although shifts in the distribution and boundaries of the major malaria vectors (Anopheles gambiae s.s. and An. arabiensis) across Africa have been predicted, quantified areas of absolute change in zone of suitability for their survival have not been defined. In this study, we have quantified areas of absolute change conducive for the establishment and survival of these vectors, per African country, under two climate change scenarios and based on our findings, highlight practical measures for effective malaria control in the face of changing climatic patterns. Methods We developed a model using CLIMEX simulation platform to estimate the potential geographical distribution and seasonal abundance of these malaria vectors in relation to climatic factors (temperature, rainfall and relative humidity). The model yielded an eco-climatic index (EI) describing the total favourable geographical locations for the species. The EI values were classified and exported to a GIS package. Using ArcGIS, the EI shape points were clipped to the extent of Africa and then converted to a raster layer using Inverse Distance Weighted (IDW) interpolation method. Generated maps were then transformed into polygon-based geo-referenced data set and their areas computed and expressed in square kilometers (km2). Results Five classes of EI were derived indicating the level of survivorship of these malaria vectors. The proportion of areas increasing or decreasing in level of survival of these malaria vectors will be more pronounced in eastern and southern African countries than those in western Africa. Angola, Ethiopia, Kenya, Mozambique, Tanzania, South Africa and Zambia appear most likely to be affected in terms of absolute change of malaria vectors suitability zones under the selected climate change scenarios. Conclusion The potential shifts of these malaria vectors have implications for human exposure to malaria, as recrudescence of the disease is likely to be recorded in several new areas and regions. Therefore, the need to develop, compile and share malaria preventive measures, which can be adapted to different climatic scenarios, remains crucial. PMID:24885061
Climate Change and Spatiotemporal Distributions of Vector-Borne Diseases in Nepal � A Systematic Synthesis of Literature
Dhimal, Meghnath; Ahrens, Bodo; Kuch, Ulrich
Background Despite its largely mountainous terrain for which this Himalayan country is a popular tourist destination, Nepal is now endemic for five major vector-borne diseases (VBDs), namely malaria, lymphatic filariasis, Japanese encephalitis, visceral leishmaniasis and dengue fever. There is increasing evidence about the impacts of climate change on VBDs especially in tropical highlands and temperate regions. Our aim is to explore whether the observed spatiotemporal distributions of VBDs in Nepal can be related to climate change. Methodology A systematic literature search was performed and summarized information on climate change and the spatiotemporal distribution of VBDs in Nepal from the published literature until December2014 following providing items for systematic review and meta-analysis (PRISMA) guidelines. Principal Findings We found 12 studies that analysed the trend of climatic data and are relevant for the study of VBDs, 38 studies that dealt with the spatial and temporal distribution of disease vectors and disease transmission. Among 38 studies, only eight studies assessed the association of VBDs with climatic variables. Our review highlights a pronounced warming in the mountains and an expansion of autochthonous cases of VBDs to non-endemic areas including mountain regions (i.e., at least 2,000 m above sea level). Furthermore, significant relationships between climatic variables and VBDs and their vectors are found in short-term studies. Conclusion Taking into account the weak health care systems and difficult geographic terrain of Nepal, increasing trade and movements of people, a lack of vector control interventions, observed relationships between climatic variables and VBDs and their vectors and the establishment of relevant disease vectors already at least 2,000 m above sea level, we conclude that climate change can intensify the risk of VBD epidemics in the mountain regions of Nepal if other non-climatic drivers of VBDs remain constant. PMID:26086887
Power balancing in variable speed wind-energy systems using vector control of front-end converters
Roberto C�rdenas; Rub�n Pe�a; Marcelo P�rez; Fernando Vargas; Greg Asher; Jon Clare
This paper presents a novel power balance control method for wind energy systems feeding an isolated grid. The system is based on a variable-speed wind energy conversion system (WECS) connected to an AC load using a power converter. An energy storage system, connected to the AC load using an additional converter, is used to balance the power generated by the
Downscaling of precipitation for climate change scenarios: A support vector machine approach
NASA Astrophysics Data System (ADS)
Tripathi, Shivam; Srinivas, V. V.; Nanjundiah, Ravi S.
SummaryThe Climate impact studies in hydrology often rely on climate change information at fine spatial resolution. However, general circulation models (GCMs), which are among the most advanced tools for estimating future climate change scenarios, operate on a coarse scale. Therefore the output from a GCM has to be downscaled to obtain the information relevant to hydrologic studies. In this paper, a support vector machine (SVM) approach is proposed for statistical downscaling of precipitation at monthly time scale. The effectiveness of this approach is illustrated through its application to meteorological sub-divisions (MSDs) in India. First, climate variables affecting spatio-temporal variation of precipitation at each MSD in India are identified. Following this, the data pertaining to the identified climate variables (predictors) at each MSD are classified using cluster analysis to form two groups, representing wet and dry seasons. For each MSD, SVM- based downscaling model (DM) is developed for season(s) with significant rainfall using principal components extracted from the predictors as input and the contemporaneous precipitation observed at the MSD as an output. The proposed DM is shown to be superior to conventional downscaling using multi-layer back-propagation artificial neural networks. Subsequently, the SVM-based DM is applied to future climate predictions from the second generation Coupled Global Climate Model (CGCM2) to obtain future projections of precipitation for the MSDs. The results are then analyzed to assess the impact of climate change on precipitation over India. It is shown that SVMs provide a promising alternative to conventional artificial neural networks for statistical downscaling, and are suitable for conducting climate impact studies.
Wind-driven changes in Southern Ocean residual circulation, ocean carbon reservoirs and atmospheric CO2
NASA Astrophysics Data System (ADS)
Lauderdale, Jonathan M.; Garabato, Alberto C. Naveira; Oliver, Kevin I. C.; Follows, Michael J.; Williams, Richard G.
The effect of idealized wind-driven circulation changes in the Southern Ocean on atmospheric CO2 and the ocean carbon inventory is investigated using a suite of coarse-resolution, global coupled ocean circulation and biogeochemistry experiments with parameterized eddy activity and only modest changes in surface buoyancy forcing, each experiment integrated for 5,000 years. A positive correlation is obtained between the meridional overturning or residual circulation in the Southern Ocean and atmospheric CO2: stronger or northward-shifted westerly winds in the Southern Hemisphere result in increased residual circulation, greater upwelling of carbon-rich deep waters and oceanic outgassing, which increases atmospheric pCO2 by �20 ?atm; weaker or southward-shifted winds lead to the opposing result. The ocean carbon inventory in our model varies through contrasting changes in the saturated, disequilibrium and biogenic (soft-tissue and carbonate) reservoirs, each varying by O(10-100) PgC, all of which contribute to the net anomaly in atmospheric CO2. Increased residual overturning deepens the global pycnocline, warming the upper ocean and decreasing the saturated carbon reservoir. Increased upwelling of carbon- and nutrient-rich deep waters and inefficient biological activity results in subduction of unutilized nutrients into the ocean interior, decreasing the biogenic carbon reservoir of intermediate and mode waters ventilating the Northern Hemisphere, and making the disequilibrium carbon reservoir more positive in the mode waters due to the reduced residence time at the surface. Wind-induced changes in the model carbon inventory are dominated by the response of the global pycnocline, although there is an additional abyssal response when the peak westerly winds change their latitude, altering their proximity to Drake Passage and changing the depth extent of the southward return flow of the overturning: a northward shift of the westerly winds isolates dense isopycnals, allowing biogenic carbon to accumulate in the deep ocean of the Southern Hemisphere, while a southward shift shoals dense isopycnals that outcrop in the Southern Ocean and reduces the biogenic carbon store in the deep ocean.
RNA-seq analyses of blood-induced changes in gene expression in the mosquito vector species, Aedes aegypti
Background Hematophagy is a common trait of insect vectors of disease. Extensive genome-wide transcriptional changes occur in mosquitoes after blood meals, and these are related to digestive and reproductive processes, among others. Studies of these changes are expected to reveal molecular targets for novel vector control and pathogen transmission-blocking strategies. The mosquito Aedes aegypti (Diptera, Culicidae), a vector of Dengue viruses, Yellow Fever Virus (YFV) and Chikungunya virus (CV), is the subject of this study to look at genome-wide changes in gene expression following a blood meal. Results Transcriptional changes that follow a blood meal in Ae. aegypti females were explored using RNA-seq technology. Over 30% of more than 18,000 investigated transcripts accumulate differentially in mosquitoes at five hours after a blood meal when compared to those fed only on sugar. Forty transcripts accumulate only in blood-fed mosquitoes. The list of regulated transcripts correlates with an enhancement of digestive activity and a suppression of environmental stimuli perception and innate immunity. The alignment of more than 65 million high-quality short reads to the Ae. aegypti reference genome permitted the refinement of the current annotation of transcript boundaries, as well as the discovery of novel transcripts, exons and splicing variants. Cis-regulatory elements (CRE) and cis-regulatory modules (CRM) enriched significantly at the 5'end flanking sequences of blood meal-regulated genes were identified. Conclusions This study provides the first global view of the changes in transcript accumulation elicited by a blood meal in Ae. aegypti females. This information permitted the identification of classes of potentially co-regulated genes and a description of biochemical and physiological events that occur immediately after blood feeding. The data presented here serve as a basis for novel vector control and pathogen transmission-blocking strategies including those in which the vectors are modified genetically to express anti-pathogen effector molecules. PMID:21276245
Engineering changes to the 0.1m cryogenic wind tunnel at Southampton University
NASA Technical Reports Server (NTRS)
Goodyer, M. J.
The more important changes to the 0.1 m cryogenic wind tunnel since its completion in 1977 are outlined. These include detailed improvements in the fan drive to allow higher speeds, and the provision of a test section leg suitable for use with a magnetic suspension and balance system. The instrumentation, data logging, data reduction and tunnel controls were also improved and modernized. A tunnel performance summary is given.
Q-Winds satellite hurricane wind retrievals and H*Wind comparisons
Hennon, Christopher C.
1 Q-Winds satellite hurricane wind retrievals and H*Wind comparisons Pet Laupattarakasem and W This paper presents a new hurricane ocean vector wind (OVW) product known as Q-Winds produced from the SeaWinds for tropical cyclones. SeaWinds OVW retrievals are presented for ten hurricane passes with near
An assessment of wind energy potential in Iberia under climate change
NASA Astrophysics Data System (ADS)
Liberato, Margarida L. R.; Santos, Jo�o A.; Rochinha, Carlos; Reyers, Mark; Pinto, Joaquim G.
Wind energy potential in Iberia is assessed for recent-past (1961-2000) and future (2041-2070) climates. For recent-past, a COSMO-CLM simulation driven by ERA-40 is used. COSMO-CLM simulations driven by ECHAM5 following the A1B scenario are used for future projections. A 2 MW rated power wind turbine is selected. Mean potentials, inter-annual variability and irregularity are discussed on annual/seasonal scales and on a grid resolution of 20 km. For detailed regional assessments eight target sites are considered. For recent-past conditions, the highest daily mean potentials are found in winter over northern and eastern Iberia, particularly on high-elevation or coastal regions. In northwestern Iberia, daily potentials frequently reach maximum wind energy output (50 MWh day-1), particularly in winter. Southern Andaluc�a reveals high potentials throughout the year, whereas the Ebro valley and central-western coast show high potentials in summer. The irregularity in annual potentials is moderate (<15% of mean output), but exacerbated in winter (40%). Climate change projections show significant decreases over most of Iberia (<2 MWh day-1). The strong enhancement of autumn potentials in Southern Andaluc�a is noteworthy (>2 MWh day-1). The northward displacement of North Atlantic westerly winds (autumn-spring) and the strengthening of easterly flows (summer) are key drivers of future projections. Santos, J.A.; Rochinha, C.; Liberato, M.L.R.; Reyers, M.; Pinto, J.G. (2015) Projected changes in wind energy potentials over Iberia. Renewable Energy, 75, 1: 68-80. doi: 10.1016/j.renene.2014.09.026 Acknowledgements: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Funda��o para a Ci�ncia e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER-019524 (PTDC/AAC-CLI/121339/2010).
Climate variability and change in the United States: potential impacts on vector- and rodent-borne diseases.
Gubler, D J; Reiter, P; Ebi, K L; Yap, W; Nasci, R; Patz, J A
Diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, were once common in the United States. Many of these diseases are no longer present, mainly because of changes in land use, agricultural methods, residential patterns, human behavior, and vector control. However, diseases that may be transmitted to humans from wild birds or mammals (zoonoses) continue to circulate in nature in many parts of the country. Most vector-borne diseases exhibit a distinct seasonal pattern, which clearly suggests that they are weather sensitive. Rainfall, temperature, and other weather variables affect in many ways both the vectors and the pathogens they transmit. For example, high temperatures can increase or reduce survival rate, depending on the vector, its behavior, ecology, and many other factors. Thus, the probability of transmission may or may not be increased by higher temperatures. The tremendous growth in international travel increases the risk of importation of vector-borne diseases, some of which can be transmitted locally under suitable circumstances at the right time of the year. But demographic and sociologic factors also play a critical role in determining disease incidence, and it is unlikely that these diseases will cause major epidemics in the United States if the public health infrastructure is maintained and improved. PMID:11359689
Global auroral responses to abrupt solar wind changes: Dynamic pressure, substorm, and null events
NASA Astrophysics Data System (ADS)
Lyons, L. R.; Lee, D.-Y.; Wang, C.-P.; Mende, S. B.
Global auroral images are used to investigate how specific types of solar wind change relate to the resulting type of auroral-region disturbance, with the goal of determining fundamental response types. For not strongly southward IMF conditions (Bz ? -5 nT), we find that IMF changes that are expected to reduce the convection electric field after ?30 min of negative IMF Bz cause typical substorms, where expansion phase auroral activity initiates within the expected location of the Harang electric field reversal and expands in �10 min to cover �5 hours of MLT. For not strongly southward IMF conditions, solar wind dynamic pressure (Pdyn) enhancements compress the entire magnetosphere, leading to a global auroral enhancement with no evidence for substorm bulge-region aurora or current wedge formation. Following prolonged strongly southward IMF (Bz ? -8 nT), an IMF change leading to convection electric field reduction gives a substorm disturbance that is not much different from substorms for less strongly southward IMF conditions, other than the expansion phase auroral bulge region seems to expand somewhat more in azimuth. However, under steady, strongly southward IMF conditions, a Pdyn enhancement is found to cause both compressive auroral brightening away from the bulge region and a Harang-region substorm auroral brightening. These two auroral enhancements merge together, leading to a very broad auroral enhancement covering �10-15 hours of MLT. Both current wedge formation and compressive energization in the inner plasma sheet apparently occur for these events. We also find that interplay of effects from a simultaneous IMF and Pdyn change can prevent the occurrence of a substorm, leading to what we refer to as null events. Finally, we apply the plasma sheet continuity equation to the IMF and pressure driven substorm responses and the null events. This application suggests that solar wind changes cause substorm onset only if the changes lead to a reduction in the strength of convection within the inner plasma sheet.
Mapping the interacting winds of Eta Carinae: Changes Across the Apastron
NASA Astrophysics Data System (ADS)
Gull, Theodore R.; Madura, T.; Corcoran, M. F.; Hamaguchi, K.; Teodoro, M.
Since the May 2009 servicing mission to repair the Hubble Space Telescope, we have systematically mapped the central 1-2" region of Eta Carinae with the 0.1"-wide, long slit of the Space Telescope Imaging Spectrograph. Six mappings of selected forbidden emission lines began in the late recovery after the 2009.1 periastron event and now extend to phase 0.85 of Eta Carina's 5.54 year period. In addition to the recovery of the high state as depicted by [Fe III] (IP=16.6 eV) strictures and the stabilization of [Fe II] (IP=7.8 eV) features, we see components of at least three wind-blown shells that expand outward at 400 to 500 km/s. Virtually all forbidden emission originates from primary wind structures. The [Fe II] shells, moving at 470 km/s, are primary wind (420 km/s) structures slightly accelerated by the fast secondary wind (Teodoro et al, 2013 ApJ 773, L16T). The [Fe III] arcs, directly photo-ionized by the secondary star, also shift outward with time. Structures in both emissions shift in a general clockwork direction consistent with the derived orbital motion by Gull et al (2009 MNRAS 396, 1308) and revised by Madura et al (2012 MNRAS 420, 2064). With the continued development of the 3D hydrodynamic models we are able to compare the changing structures and determine limits to changes in the mass loss rate over this period of time. Additional mappings, to be obtained by seven additional HST visits, are scheduled at selected orbital phases to follow major changes in ionization structue due to the drop of high ionization to low ionization across the 2014.5 periastron passage. This work is funded by NASA grants to support HST research.
Assessment of changes in extreme wind speeds from regional climate models
NASA Astrophysics Data System (ADS)
Kunz, Michael; Rauthe, Monika; Mohr, Susanna
Extratropical cyclones that usually develop and amplify over the Northern Atlantic are characteristic compartments of Europeans climate. Associated destructive wind speeds along with a large horizontal extent may cause substantial amount of damage. In Central Europe, winter storms are responsible for more than the half of the total economic loss caused by natural hazards. In light of global warming it is an important and still open question to what extent the frequency and/or intensity of severe winter storms may change by greenhouse gas forcing conditions (IPCC, 2007). To study regional impacts of climate change on the local storm climatology in Central Europe, different scenarios from two regional climate models (RCM) with a horizontal resolution of 10 and 18 km, respectively, are used. We considered three emission scenarios (A1B, B1, A2) and two RCMs, the Regional Model (REMO) and the Consortium for Small-scale Modelling (CCLM), where the latter is initialized by two different runs of the global climate model ECHAM5/MPI-OM. Extreme value statistics are applied to calculate gust wind speeds for a specific return period at each grid point. Changes in the regional storm climate are quantified by differences in the gusts between a projection period (2021-2050) and a control period (1971-2000). The evaluation of extreme wind speeds for a 10-year return period within the control period show that the spatial patterns as well as the characteristics of extremes are quite well reproduced by the models. The magnitude of the gusts, however, are significantly underestimated by 10 to 30%. This can be attributed to deficiencies in the gust parameterization schemes and the coarse resolution of the model chain which is unable to reproduce strong pressure gradients. These effects, however, will vanish when considering relative differences between two different time periods. Expected changes in extreme wind speeds for the future show a high variability both between the grid points and the different scenarios. It is found that the spatial patterns of relative changes are mostly controlled by the global model, whereas differences between the emission scenarios A1B and B1 as well as the RCMs are of minor importance. For Northern Germany, the RCMs suggest an increase in extreme wind speed for a 10-year return period between +2 and +6%, whereas for Southern Germany a decrease between 0 and -4% is expected.
Opportunities and challenges in assessing climate change impacts on wind energy�a critical comparison of wind speed projections in California
NASA Astrophysics Data System (ADS)
Rasmussen, D. J.; Holloway, T.; Nemet, G. F.
Future climate change is expected to alter the spatial and temporal distribution of surface wind speeds (SWS), with associated impacts on electricity generation from wind energy. However, the predictions for the direction and magnitude of these changes hinge critically on the assessment methods used. Many climate change impact analyses, including those focused on wind energy, use individual climate models and/or statistical downscaling methods rooted in historical observations. Such studies may individually suggest an unrealistically high level of scientific certainty due to the absence of competing projections (over the same region, time period, etc). A new public data archive, the North American Regional Climate Change Assessment Program (NARCCAP), allows for a more comprehensive perspective on regional climate change impacts, here applied to three wind farm sites in California. We employ NARCCAP regional climate model data to estimate changes in SWS expected to occur in the mid-21st century at three wind farm regions: Altamont Pass, San Gorgonio Pass, and Tehachapi Pass. We examined trends in SWS magnitude and frequency using three different global/regional model pairs, focused on model evaluation, seasonal cycle, and long-term trends. Our results, while specific to California, highlight the opportunities and limitations in NARCCAP and other publicly available meteorological data sets for energy analysis, and the importance of using multiple models for climate change impact assessment. Although spatial patterns in current wind conditions agree fairly well among models and with NARR (North American Regional Reanalysis) data, results vary widely at our three sites of interest. This poor performance and model disagreement may be explained by complex topography, limited model resolution, and differences in model physics. Spatial trends and site-specific estimates of annual average changes (1980-2000 versus 2051-71) also differed widely across models. All models predicted changes of < 2% at each site, but the direction of the change varies. However, decreases of < 2% in resources at Altamont Pass are agreed upon by each NARCCAP model used. This lack of model agreement suggests uncertainty in future changes, and a potentially high degree of risk for future investors in wind-generated electricity. More broadly, our study highlights the need for multiple calculation approaches to help distinguish between robust and method-dependent results.
Changing patterns of West Nile virus transmission: altered vector competence and host susceptibility
Brault, Aaron C.
West Nile virus (WNV) is a flavivirus (Flaviviridae) transmitted between Culex spp. mosquitoes and avian hosts. The virus has dramatically expanded its geographic range in the past ten years. Increases in global commerce, climate change, ecological factors and the emergence of novel viral genotypes likely play significant roles in the emergence of this virus; however, the exact mechanism and relative importance of each is uncertain. Previously WNV was primarily associated with febrile illness of children in endemic areas, but it was identified as a cause of neurological disease in humans in 1994. This modulation in disease presentation could be the result of the emergence of a more virulent genotype as well as the progression of the virus into areas in which the age structure of immunologically na�ve individuals makes them more susceptible to severe neurological disease. Since its introduction to North America in 1999, a novel WNV genotype has been identified that has been demonstrated to disseminate more rapidly and with greater efficiency at elevated temperatures than the originally introduced strain, indicating the potential importance of temperature as a selective criteria for the emergence of WNV genotypes with increased vectorial capacity. Even prior to the North American introduction, a mutation associated with increased replication in avian hosts, identified to be under adaptive evolutionary pressure, has been identified, indicating that adaptation for increased replication within vertebrate hosts could play a role in increased transmission efficiency. Although stable in its evolutionary structure, WNV has demonstrated the capacity for rapidly adapting to both vertebrate hosts and invertebrate vectors and will likely continue to exploit novel ecological niches as it adapts to novel transmission foci. PMID:19406093
Histomorphometric analysis of the temporal bone after change of direction of force vector of mandible: an experimental study in rabbits
PURICELLI, Edela; PONZONI, Deise; MUNARETTO, J�ssica Cerioli; CORSETTI, Adriana; LEITE, Mauro Gomes Trein
Objectives The present study aimed at performing a histological evaluation of the response of temporal bone tissue to a change of direction of the force vector of the mandible in relation to the base of the skull. Material and methods Adult rabbits were assigned into four groups with two control and four experimental animals in each group. Experimental animals underwent surgery, which resulted in a change of direction of the force vector on the right temporomandibular joint. Samples were collected after 15, 30, 60 and 90 days for histological analysis. Results In the two-way analysis of variance, the effect of group and time was statistically significant (p<0.001). Additionally, a statistically significant interaction between group and time was observed (p<0.001). Control animals showed normal growth and development of the temporal region. In the experimental group, the change in direction of the force vector of the mandible induced significant changes in the temporal bone, with a bone modeling process, which suggests growth of this cranial structure. Conclusions The methodology used in this experiment allows us to conclude that the change in direction of the force vector of the mandible in relation to the skull base induces remodeling and modeling processes in the temporal bone. The resumption of normal oral functions after bone healing of the mandibular fracture appears to increase cell activation in the remodeling and modeling of the temporal bone structure. The observation of areas of temporal bone modeling shows the relevance of further investigation on the correlation between the joint structures and craniofacial growth and development. PMID:23138738
Determination of statistics for any rotation of axes of a bivariate normal elliptical distribution. [of wind vector components
NASA Technical Reports Server (NTRS)
Falls, L. W.; Crutcher, H. L.
Transformation of statistics from a dimensional set to another dimensional set involves linear functions of the original set of statistics. Similarly, linear functions will transform statistics within a dimensional set such that the new statistics are relevant to a new set of coordinate axes. A restricted case of the latter is the rotation of axes in a coordinate system involving any two correlated random variables. A special case is the transformation for horizontal wind distributions. Wind statistics are usually provided in terms of wind speed and direction (measured clockwise from north) or in east-west and north-south components. A direct application of this technique allows the determination of appropriate wind statistics parallel and normal to any preselected flight path of a space vehicle. Among the constraints for launching space vehicles are critical values selected from the distribution of the expected winds parallel to and normal to the flight path. These procedures are applied to space vehicle launches at Cape Kennedy, Florida.
Predicted altitudinal shifts and reduced spatial distribution of Leishmania infantum vector species under climate change scenarios in Colombia.
Gonz�lez, Camila; Paz, Andrea; Ferro, Cristina
Visceral leishmaniasis (VL) is caused by the trypanosomatid parasite Leishmania infantum (=Leishmania chagasi), and is epidemiologically relevant due to its wide geographic distribution, the number of annual cases reported and the increase in its co-infection with HIV. Two vector species have been incriminated in the Americas: Lutzomyia longipalpis and Lutzomyia evansi. In Colombia, L. longipalpis is distributed along the Magdalena River Valley while L. evansi is only found in the northern part of the Country. Regarding the epidemiology of the disease, in Colombia the incidence of VL has decreased over the last few years without any intervention being implemented. Additionally, changes in transmission cycles have been reported with urban transmission occurring in the Caribbean Coast. In Europe and North America climate change seems to be driving a latitudinal shift of leishmaniasis transmission. Here, we explored the spatial distribution of the two known vector species of L. infantum in Colombia and projected its future distribution into climate change scenarios to establish the expansion potential of the disease. An updated database including L. longipalpis and L. evansi collection records from Colombia was compiled. Ecological niche models were performed for each species using the Maxent software and 13 Worldclim bioclimatic coverages. Projections were made for the pessimistic CSIRO A2 scenario, which predicts the higher increase in temperature due to non-emission reduction, and the optimistic Hadley B2 Scenario predicting the minimum increase in temperature. The database contained 23 records for L. evansi and 39 records for L. longipalpis, distributed along the Magdalena River Valley and the Caribbean Coast, where the potential distribution areas of both species were also predicted by Maxent. Climate change projections showed a general overall reduction in the spatial distribution of the two vector species, promoting a shift in altitudinal distribution for L. longipalpis and confining L. evansi to certain regions in the Caribbean Coast. Altitudinal shifts have been reported for cutaneous leishmaniasis vectors in Colombia and Peru. Here, we predict the same outcome for VL vectors in Colombia. Changes in spatial distribution patterns could be affecting local abundances due to climatic pressures on vector populations thus reducing the incidence of human cases. PMID:23988300
A mechanism for decadal changes of ENSO behavior: roles of background wind changes
B. Wang; S. I. An
This study explains why a number of El Nino properties (period, amplitude, structure, and propagation) have changed in a coherent manner since the late 1970s and why these changes had almost concurred with the Pacific decadal climate shift. Evidence is presented to show that from the pre-shift (1961-1975) to the post-shift (1981-1995) epoch, significant changes in the tropical Pacific are
Modelling the influence of predicted future climate change on the risk of wind damage within New Zealand's planted forests.
Moore, John R; Watt, Michael S
Wind is the major abiotic disturbance in New Zealand's planted forests, but little is known about how the risk of wind damage may be affected by future climate change. We linked a mechanistic wind damage model (ForestGALES) to an empirical growth model for radiata pine (Pinus radiata D. Don) and a process-based growth model (cenw) to predict the risk of wind damage under different future emissions scenarios and assumptions about the future wind climate. The cenw model was used to estimate site productivity for constant CO2 concentration at 1990 values and for assumed increases in CO2 concentration from current values to those expected during 2040 and 2090 under the B1 (low), A1B (mid-range) and A2 (high) emission scenarios. Stand development was modelled for different levels of site productivity, contrasting silvicultural regimes and sites across New Zealand. The risk of wind damage was predicted for each regime and emission scenario combination using the ForestGALES model. The sensitivity to changes in the intensity of the future wind climate was also examined. Results showed that increased tree growth rates under the different emissions scenarios had the greatest impact on the risk of wind damage. The increase in risk was greatest for stands growing at high stand density under the A2 emissions scenario with increased CO2 concentration. The increased productivity under this scenario resulted in increased tree height, without a corresponding increase in diameter, leading to more slender trees that were predicted to be at greater risk from wind damage. The risk of wind damage was further increased by the modest increases in the extreme wind climate that are predicted to occur. These results have implications for the development of silvicultural regimes that are resilient to climate change and also indicate that future productivity gains may be offset by greater losses from disturbances. PMID:25703827
Wind power: Addressing wildlife impacts, assessing effects on tourism, and examining the link between climate change perceptions and support
NASA Astrophysics Data System (ADS)
Lilley, Meredith Blaydes
As the world's most rapidly growing source of energy, wind power has vast potential for mitigating climate change and advancing global environmental sustainability. Yet, the challenges facing wind energy remain both complex and substantial. Two such challenges are: 1) wildlife impacts; and 2) perceived negative effects on tourism. This dissertation examines these challenges in a multi-paper format, and also investigates the role that climate change perceptions play in garnering public support for wind power. The first paper assesses optimal approaches for addressing wind power's wildlife impacts. Comparative analysis reveals that avian mortality from turbines ranks far behind avian mortality from a number of other anthropogenic sources. Additionally, although bats have recently emerged as more vulnerable to wind turbines than birds, they are generally less federally protected. The Migratory Bird Treaty Act (MBTA) protects over 800 bird species, regardless of their threatened or endangered status. Moreover, it criminalizes the incidental take of birds without a permit and simultaneously grants no permits for such incidental take, thereby creating a legal conundrum for the wind industry. An examination of the legislative and case history of the MBTA, however, reveals that wind operators are not likely to be prosecuted for incidental take if they cooperate with the U.S. Fish & Wildlife Service (FWS) and take reasonable steps to reduce siting and operational impacts. Furthermore, this study's analysis reveals modest wildlife impacts from wind power, in comparison with numerous other energy sources. Scientific-research, legal, and policy recommendations are provided to update the present legal and regulatory regime under the MBTA and to minimize avian and bat impacts. For instance, FWS should: establish comprehensive federal guidelines for wind facility siting, permitting, monitoring, and mitigation; and promulgate regulations under the MBTA for the issuance of incidental take permits at wind facilities. Equal protections for bats are also recommended. In examining the potential effect of offshore wind power on coastal tourism, the second paper reports the findings of a summer 2007 survey of over 1,000 out-of-state tourists at Delaware beaches. Randomly sampled beachgoers were shown photo-simulations of wind turbines at increasing distances from shore and asked how each simulation would affect visitation. With wind turbines located six miles offshore, approximately one-quarter would switch to a different beach. This stated avoidance, however, diminishes with increasing wind project distance from shore. Additionally, stated avoidance of a beach with turbines six miles offshore is exceeded by: avoidance of a beach with an equidistant, inland, fossil fuel power plant; attraction to a beach in order to see turbines six miles offshore; and the likelihood of paying for an offshore wind boat tour. Further, logistic regression modeling reveals that neither trip cost nor income significantly influences the likelihood of visiting a beach with offshore wind. These findings suggest that to limit beach avoidance, offshore wind developers could site wind facilities further from shore, particularly in areas with high recreational use. Moreover, with wind turbines six miles offshore serving more as an attraction than as a deterrent, offshore wind development may, in fact, bolster local tourism revenues. The third study examines public perceptions of climate change and the link between those perceptions and support for wind power, both in general and with respect to specific offshore sites. Analyzing data from five surveys, this research uncovers low climate awareness and concern levels overall. Respondents demonstrate a poor understanding of climate change impacts and of how to effectively address climate change. In accordance with the New Ecological Paradigm, still fewer are concerned about climate change. The issue ranks 6th in Delaware and 8th in Cape Cod as a reason for local project support, behind such issues as energy independence
Interannual bottom pressure changes in the Arafura Sea and the remote influence of equatorial Pacific winds
NASA Astrophysics Data System (ADS)
Ponte, R. M.; Piecuch, C. G.; Quinn, K. J.
Ocean bottom pressure (OBP) is a crucial quantity for understanding changes in ocean circulation and climate, yet general knowledge of its regional variability on climate timescales is lacking. General circulation modeling studies suggest that interannual OBP changes can contribute importantly to low frequency variability in shallow shelf regions, but this suggestion has not been investigated using observations. Taking advantage of recently released ocean mass data from the Gravity Recovery and Climate Experiment (GRACE) as well as an ocean general circulation model, we investigate the nature of interannual OBP variability in the Arafura Sea between Australia and Papua New Guinea. In this region, time series from model and data agree very well (correlation coefficients >0.9), attesting to the presence of OBP variations of order 1 cm sea level equivalent with long periods (>1 yr) over large spatial scales (>750 km). These OBP changes explain most of the interannual sea level variance in this region. Moreover, these interannual OBP time series are significantly correlated with ENSO indices (correlation coefficients >0.8), suggesting ties to broader scale climate variability. Through numerical forcing experiments, we demonstrate explicitly that the OBP changes in the Arafura Sea derive mostly from remote wind forcing over the equatorial Pacific, with local wind driving playing only a minor role. A mixture of equatorially- and coastally-trapped waves is likely involved in what is primarily a baroclinic response to remote winds that leads to a strongly barotropic signal in the shallow Arafura Sea. These results suggest meaningful low frequency signals reside in GRACE data and encourage the further use of GRACE fields for investigations of regional oceanic variability on climate timescales.
NSDL National Science Digital Library
This is a high school instructional unit that features nine lessons relating to vectors. Students build understanding of vector properties as they learn airplane navigation. Problem-based learning activities include reading real-time weather maps, tracking airplanes flying in U.S. skies, calculating vector components, analyzing effects of wind velocity, and completing training segments similar to a private pilot certification program. Participants have access to help from experts at the Polaris Career Center. Comprehensive teacher guides, student guides, reference materials, and assessments are included. This resource was developed by the Center for Innovation in Science and Engineering Education (CIESE). Participation is cost-free; additional options are available for registered users.
Thrust Vectoring of a Continuous Rotating Detonation Engine by Changing the Local Injection Pressure
NASA Astrophysics Data System (ADS)
Liu, Shi-Jie; Lin, Zhi-Yong; Sun, Ming-Bo; Liu, Wei-Dong
The thrust vectoring ability of a continuous rotating detonation engine is numerically investigated, which is realized via increasing local injection stagnation pressure of half of the simulation domain compared to the other half. Under the homogeneous injection condition, both the flow-field structure and the detonation wave propagation process are analyzed. Due to the same injection condition along the inlet boundary, the outlines of fresh gas zones at different moments are similar to each other. The main flow-field features under thrust vectoring cases are similar to that under the baseline condition. However, due to the heterogeneous injection system, both the height of the fresh gas zone and the pressure value of the fresh gas in the high injection pressure zone are larger than that in the low injection pressure zone. Thus the average pressure in half of the engine is larger than that in the other half and the thrust vectoring adjustment is realized.
Impacts of Climate Change on Vector Borne Diseases in the Mediterranean Basin � Implications for Preparedness and Adaptation Policy
Negev, Maya; Paz, Shlomit; Clermont, Alexandra; Pri-Or, Noemie Groag; Shalom, Uri; Yeger, Tamar; Green, Manfred S.
The Mediterranean region is vulnerable to climatic changes. A warming trend exists in the basin with changes in rainfall patterns. It is expected that vector-borne diseases (VBD) in the region will be influenced by climate change since weather conditions influence their emergence. For some diseases (i.e., West Nile virus) the linkage between emergence andclimate change was recently proved; for others (such as dengue) the risk for local transmission is real. Consequently, adaptation and preparation for changing patterns of VBD distribution is crucial in the Mediterranean basin. We analyzed six representative Mediterranean countries and found that they have started to prepare for this threat, but the preparation levels among them differ, and policy mechanisms are limited and basic. Furthermore, cross-border cooperation is not stable and depends on international frameworks. The Mediterranean countries should improve their adaptation plans, and develop more cross-sectoral, multidisciplinary and participatory approaches. In addition, based on experience from existing local networks in advancing national legislation and trans-border cooperation, we outline recommendations for a regional cooperation framework. We suggest that a stable and neutral framework is required, and that it should address the characteristics and needs of African, Asian and European countries around the Mediterranean in order to ensure participation. Such a regional framework is essential to reduce the risk of VBD transmission, since the vectors of infectious diseases know no political borders. PMID:26084000
Impacts of Climate Change on Vector Borne Diseases in the Mediterranean Basin - Implications for Preparedness and Adaptation Policy.
Negev, Maya; Paz, Shlomit; Clermont, Alexandra; Pri-Or, Noemie Groag; Shalom, Uri; Yeger, Tamar; Green, Manfred S
The Mediterranean region is vulnerable to climatic changes. A warming trend exists in the basin with changes in rainfall patterns. It is expected that vector-borne diseases (VBD) in the region will be influenced by climate change since weather conditions influence their emergence. For some diseases (i.e., West Nile virus) the linkage between emergence andclimate change was recently proved; for others (such as dengue) the risk for local transmission is real. Consequently, adaptation and preparation for changing patterns of VBD distribution is crucial in the Mediterranean basin. We analyzed six representative Mediterranean countries and found that they have started to prepare for this threat, but the preparation levels among them differ, and policy mechanisms are limited and basic. Furthermore, cross-border cooperation is not stable and depends on international frameworks. The Mediterranean countries should improve their adaptation plans, and develop more cross-sectoral, multidisciplinary and participatory approaches. In addition, based on experience from existing local networks in advancing national legislation and trans-border cooperation, we outline recommendations for a regional cooperation framework. We suggest that a stable and neutral framework is required, and that it should address the characteristics and needs of African, Asian and European countries around the Mediterranean in order to ensure participation. Such a regional framework is essential to reduce the risk of VBD transmission, since the vectors of infectious diseases know no political borders. PMID:26084000
Spatial orientation and balance control changes induced by altered gravitoinertial force vectors
NASA Technical Reports Server (NTRS)
Kaufman, G. D.; Wood, S. J.; Gianna, C. C.; Black, F. O.; Paloski, W. H.
To better understand the mechanisms of human adaptation to rotating environments, we exposed 19 healthy subjects and 8 vestibular-deficient subjects ("abnormal"; four bilateral and four unilateral lesions) to an interaural centripetal acceleration of 1 g (resultant 45 degrees roll-tilt of 1.4 g) on a 0.8-m-radius centrifuge for periods of 90 min. The subjects sat upright (body z-axis parallel to centrifuge rotation axis) in the dark with head stationary, except during 4 min of every 10 min, when they performed head saccades toward visual targets switched on at 3- to 5-s intervals at random locations (within +/- 30 degrees) in the earth-horizontal plane. Eight of the normal subjects also performed the head saccade protocol in a stationary chair adjusted to a static roll-tilt angle of 45 degrees for 90 min (reproducing the change in orientation but not the magnitude of the gravitoinertial force on the centrifuge). Eye movements, including voluntary saccades directed along perceived earth- and head-referenced planes, were recorded before, during, and immediately after centrifugation. Postural center of pressure (COP) and multisegment body kinematics were also gathered before and within 10 min after centrifugation. Normal subjects overestimated roll-tilt during centrifugation and revealed errors in perception of head-vertical provided by directed saccades. Errors in this perceptual response tended to increase with time and became significant after approximately 30 min. Motion-sickness symptoms caused approximately 25% of normal subjects to limit their head movements during centrifugation and led three normal subjects to stop the test early. Immediately after centrifugation, subjects reported feeling tilted 10 degrees in the opposite direction, which was in agreement with the direction of their earth-referenced directed saccades. Postural COP, segmental body motion amplitude, and hip-sway frequency increased significantly after centrifugation. These postural effects were short-lived, however, with a recovery time of several postural test trials (minutes). There were also asymmetries in the direction of postcentrifugation COP and head tilt which depended on the subject's orientation during the centrifugation adaptation period (left ear or right ear out). The amount of total head movements during centrifugation correlated poorly or inversely with postcentrifugation postural stability, and the most unstable subject made no head movements. There was no decrease in postural stability after static tilt, although these subjects also reported a perceived tilt briefly after return to upright, and they also had COP asymmetries. Abnormal subjects underestimated roll-tilt during centrifugation, and their directed saccades revealed permanent spatial distortions. Bilateral abnormal subjects started out with poor postural control, but showed no postural decrements after centrifugation, while unilateral abnormal subjects had varying degrees of postural decrement, both in their everyday function and as a result of experiencing the centrifugation. In addition, three unilateral, abnormal subjects, who rode twice in opposite orientations, revealed a consistent orthogonal pattern of COP offsets after centrifugation. These results suggest that both orientation and magnitude of the gravitoinertial vector are used by the central nervous system for calibration of multiple orientation systems. A change in the background gravitoinertial force (otolith input) can rapidly initiate postural and perceptual adaptation in several sensorimotor systems, independent of a structured visual surround.
Thrust Vectoring of a Continuous Rotating Detonation Engine by Changing the Local Injection Pressure
Shi-Jie Liu; Zhi-Yong Lin; Ming-Bo Sun; Wei-Dong Liu
The thrust vectoring ability of a continuous rotating detonation engine is numerically investigated, which is realized via increasing local injection stagnation pressure of half of the simulation domain compared to the other half. Under the homogeneous injection condition, both the flow-field structure and the detonation wave propagation process are analyzed. Due to the same injection condition along the inlet boundary,
Assessment of change in hydration in women during pregnancy and postpartum with bioelectrical impedance vectors
Technology Transfer Automated Retrieval System (TEKTRAN)
Increases in total body water (TBW) are typical of late-stage pregnancy. Because excessive TBW expansion or contraction can lead to adverse outcomes, a safe non-invasive method for routine assessment of TBW would be useful clinically. Impedance vectors are derived from resistance (R) and reactance...
Wisconsin at Madison, University of
under scenarios of global warming and deforestation. With different mosquito vectors and habitat of Doctor of Philosophy (Population Health Sciences & Environment and Resources) at the University, it is not surprising that simplified, global-scale models of malaria suitability � based on the African malaria
The national assessment of shoreline change: A GIS compilation of vector shorelines and associated shoreline change data for the New England and Mid-Atlantic Coasts
Himmelstoss, Emily A.; Kratzmann, Meredith; Hapke, Cheryl; Thieler, E. Robert; List, Jeffrey
Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. The U.S. Geological Survey's National Assessment of Shoreline Change Project has compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the New England and Mid-Atlantic Coasts. There is currently no widely accepted standard for analyzing shoreline change. Existing measurement and rate-calculation methods vary from study to study and preclude combining results into statewide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.
Climate Change and Risk of Leishmaniasis in North America: Predictions from Ecological Niche Models of Vector and Reservoir Species
Gonz�lez, Camila; Wang, Ophelia; Strutz, Stavana E.; Gonz�lez-Salazar, Constantino; S�nchez-Cordero, V�ctor; Sarkar, Sahotra
Background Climate change is increasingly being implicated in species' range shifts throughout the world, including those of important vector and reservoir species for infectious diseases. In North America (M�xico, United States, and Canada), leishmaniasis is a vector-borne disease that is autochthonous in M�xico and Texas and has begun to expand its range northward. Further expansion to the north may be facilitated by climate change as more habitat becomes suitable for vector and reservoir species for leishmaniasis. Methods and Findings The analysis began with the construction of ecological niche models using a maximum entropy algorithm for the distribution of two sand fly vector species (Lutzomyia anthophora and L. diabolica), three confirmed rodent reservoir species (Neotoma albigula, N. floridana, and N. micropus), and one potential rodent reservoir species (N. mexicana) for leishmaniasis in northern M�xico and the United States. As input, these models used species' occurrence records with topographic and climatic parameters as explanatory variables. Models were tested for their ability to predict correctly both a specified fraction of occurrence points set aside for this purpose and occurrence points from an independently derived data set. These models were refined to obtain predicted species' geographical distributions under increasingly strict assumptions about the ability of a species to disperse to suitable habitat and to persist in it, as modulated by its ecological suitability. Models successful at predictions were fitted to the extreme A2 and relatively conservative B2 projected climate scenarios for 2020, 2050, and 2080 using publicly available interpolated climate data from the Third Intergovernmental Panel on Climate Change Assessment Report. Further analyses included estimation of the projected human population that could potentially be exposed to leishmaniasis in 2020, 2050, and 2080 under the A2 and B2 scenarios. All confirmed vector and reservoir species will see an expansion of their potential range towards the north. Thus, leishmaniasis has the potential to expand northwards from M�xico and the southern United States. In the eastern United States its spread is predicted to be limited by the range of L. diabolica; further west, L. anthophora may play the same role. In the east it may even reach the southern boundary of Canada. The risk of spread is greater for the A2 scenario than for the B2 scenario. Even in the latter case, with restrictive (contiguous) models for dispersal of vector and reservoir species, and limiting vector and reservoir species occupancy to only the top 10% of their potential suitable habitat, the expected number of human individuals exposed to leishmaniasis by 2080 will at least double its present value. Conclusions These models predict that climate change will exacerbate the ecological risk of human exposure to leishmaniasis in areas outside its present range in the United States and, possibly, in parts of southern Canada. This prediction suggests the adoption of measures such as surveillance for leishmaniasis north of Texas as disease cases spread northwards. Potential vector and reservoir control strategies�besides direct intervention in disease cases�should also be further investigated. PMID:20098495
Characterization of the intrinsic and forced variability and climate change evolution of the wind speed in the iberian peninsula
NASA Astrophysics Data System (ADS)
Cabos, William; G�mez, Guillermo; Sein, Dmitry; Liguori, Giovanni; de Frutos, Jos� Antonio
We quantify the impact of climate change on the surface wind speed field over the Iberian Peninsula (IP) using the results of high-resolution EURO-CORDEX ensemble simulations. The dependence of the robustness of the regional climate signal for the wind on the global forcing is investigated. For this purpose we take simulations where different regional models forced by the same Global Coupled Model or Earth System Model. We also evaluate the dependence of the robustness of the climate signal for a given Regional Climate Model, when it is forced by different Global Models. To this end, regions of the Iberian Peninsula with coherent temporal variability in wind speed in each of the models are identified and analyzed using cluster analysis. Then, the robustness of the evolution of the simulated wind speed under the RCP climate change scenarios in the identified regions for the 2031-2050 and 2081-2100 periods in the Iberian Peninsula is analyzed.
Wind Tunnel Test of an RPV with Shape-Change Control Effector and Sensor Arrays
NASA Technical Reports Server (NTRS)
Raney, David L.; Cabell, Randolph H.; Sloan, Adam R.; Barnwell, William G.; Lion, S. Todd; Hautamaki, Bret A.
A variety of novel control effector concepts have recently emerged that may enable new approaches to flight control. In particular, the potential exists to shift the composition of the typical aircraft control effector suite from a small number of high authority, specialized devices (rudder, aileron, elevator, flaps), toward larger numbers of smaller, less specialized, distributed device arrays. The concept envisions effector and sensor networks composed of relatively small high-bandwidth devices able to simultaneously perform a variety of control functions using feedback from disparate data sources. To investigate this concept, a remotely piloted flight vehicle has been equipped with an array of 24 trailing edge shape-change effectors and associated pressure measurements. The vehicle, called the Multifunctional Effector and Sensor Array (MESA) testbed, was recently tested in NASA Langley's 12-ft Low Speed wind tunnel to characterize its stability properties, control authorities, and distributed pressure sensitivities for use in a dynamic simulation prior to flight testing. Another objective was to implement and evaluate a scheme for actively controlling the spanwise pressure distribution using the shape-change array. This report describes the MESA testbed, design of the pressure distribution controller, and results of the wind tunnel test.
Electrostatic Solitary Waves in the Solar Wind: Evidence for Instability at Solar Wind Current Sheets
NASA Technical Reports Server (NTRS)
Malaspina, David M.; Newman, David L.; Wilson, Lynn Bruce; Goetz, Keith; Kellogg, Paul J.; Kerstin, Kris
A strong spatial association between bipolar electrostatic solitary waves (ESWs) and magnetic current sheets (CSs) in the solar wind is reported here for the first time. This association requires that the plasma instabilities (e.g., Buneman, electron two stream) which generate ESWs are preferentially localized to solar wind CSs. Distributions of CS properties (including shear angle, thickness, solar wind speed, and vector magnetic field change) are examined for differences between CSs associated with ESWs and randomly chosen CSs. Possible mechanisms for producing ESW-generating instabilities at solar wind CSs are considered, including magnetic reconnection.
Global Climate Change and Its Potential Impact on Disease Transmission by Salinity-Tolerant Mosquito Vectors in Coastal Zones
Ramasamy, Ranjan; Surendran, Sinnathamby Noble
Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5?ppt or parts per thousand, 0.5�30?ppt and >30?ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross�McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased coastal transmission of mosquito-borne diseases consequent to climate change and a rise in sea levels. It is proposed that the Jaffna peninsula in Sri Lanka may be a useful case study for the impact of rising sea levels on mosquito vectors in tropical coasts. PMID:22723781
Do changes in the size of mud flocs affect the acoustic backscatter values recorded by a Vector ADV?
NASA Astrophysics Data System (ADS)
Rouhnia, Mohamad; Keyvani, Ali; Strom, Kyle
A series of experiments were conducted to examine the effect of mud floc growth on the acoustic back-scatter signal recorded by a Nortek Vector acoustic Doppler velocimeter (ADV). Several studies have shown that calibration equations can be developed to link the backscatter strength with average suspended sediment concentration (SSC) when the sediment particle size distribution remains constant. However, when mud is present, the process of flocculation can alter the suspended particle size distribution. Past studies have shown that it is still unclear as to the degree of dependence of the calibration equation on changes in floc size. Part of the ambiguity lies in the fact that flocs can be porous and rather loosely packed and therefore will not scatter sound waves as a solid particle would. In addition, direct, detailed measurements of floc size have not accompanied experiments examining the dependence of ADV backscatter and suspended sediment concentration. In this set of experiments, direct measurement of the floc size distribution is made with time in a mixing chamber using a floc camera system. A Vector ADV and an OBS are also placed within the tank to measure acoustic backscatter and SSC as the flocs change size with time; concentration in the experiments ranges from 15 to 90 mg/l. Results showed that the growth of mud flocs did influence the SNR recorded by the Vector ADV, and that the sensitivity of the SNR signal to changes in floc size was higher for flocs with diameters less than ?80 ?m (it kr=1 at a diameter of 80 ?m). The response of SNR to changes in floc size and SSC was modeled with a modified sonar equation. If properly calibrated, the model was able to capture the functional behavior of SNR with changes in floc size and concentration. Values of the calibration coefficients showed that while changes in floc diameter up to about 80 ?m did alter the SNR, the change was less than what would be expected from a similar change in the size of solid scatterers.
Assessing Southern Hemisphere Westerly Wind Changes during the Last Glacial Maximum using Paleo-data Synthesis (Invited)
NASA Astrophysics Data System (ADS)
Kohfeld, K. E.; Graham, R. M.; De Boer, A. M.; Wolff, E. W.; Sime, L. C.; Le Quere, C.; Bopp, L.
Changes in the strength and position of Southern Hemisphere westerly winds during the last glacial cycle have been invoked to explain glacial-interglacial climate fluctuations. However, neither paleo models nor paleodata agree on the magnitude, or even the sign, of the change in wind strength and latitude during the Last Glacial Maximum (LGM), compared to the recent past. This study synthesizes paleo-environmental data that have been used to infer changes in winds during the LGM compared with the late Holocene. These compilations include changes in terrestrial moisture, dust deposition, and ocean productivity, along with summaries of previously published information on sea surface temperatures (SSTs) and ocean dynamics in the Southern Hemisphere. Our compilations of terrestrial moisture from 94 sites and dust deposition from 87 sites show generally drier conditions for the LGM between 0 and 40S, with wetter conditions along the west coasts and drying along the east coasts of continents. LGM dust deposition rates ranged from 2 to 4.5 times higher over the Southern Ocean and about 13 times higher over the Antarctic continent. For the oceans, reconstructed changes in SSTs show maximum cooling (>4 �C) in the modern-day Subantarctic Zone, coincident with a region of enhanced export production during the LGM compared with today. We find that any hypothesis of LGM wind and climate change needs to provide a plausible explanation for increased moisture on the west coast of continents, cooler temperatures and higher productivity in the Subantarctic Zone, and reductions in Agulhas leakage around southern Africa. Our comparison suggests that an overall strengthening, an equatorward displacement, or no change at all in winds could all be interpreted as consistent with observations. If a single cause related to the southern westerlies is sought for all the evidence presented, then an equatorward displacement or strengthening of the winds would be consistent with the largest proportion of the data evidence. However, other processes, such as weakening or poleward shifts in winds, a weakened hydrological cycle, extended sea-ice cover, and changed buoyancy fluxes, cannot be ruled out as potential explanations of observed changes in moisture, surface temperature, and productivity. We contend that resolving the position and strength of westerly winds during the LGM remains elusive based on data reconstructions alone. However, we believe that these data reconstructions of environmental conditions can be used in conjunction with model simulations to identify which processes best represent westerly wind conditions during the LGM.
Regional patterns of surface wind change over the tropical Indo-Pacific: Evidence of the Walker circulation slowdown
NASA Astrophysics Data System (ADS)
Tokinaga, H.; Xie, S.; Timmermann, A.; McGregor, S.; Ogata, T.; Kubota, H.; Okumura, Y.
A strong linkage between changes in the Walker circulation and tropical sea surface temperature (SST) is evident in satellite observations. For instance, a strengthening of the Walker circulation is observed by satellite wind measurements in recent decades, accompanied by intensified zonal SST and sea level height gradients. On the other hand, climate models predict that the Walker circulation slows down in response to global warming through hydrological cycle changes. We investigate these mechanisms for the observed Walker circulation changes over the last six decades, with a focus on physical consistency among surface wind, cloud, sea level pressure (SLP), subsurface ocean temperature, and SST. Our bias-corrected surface wind dataset displays westerly trends over the western tropical Pacific and easterly trends over the tropical Indian Ocean, indicative of a slowdown of the Walker circulation. This pattern of wind change is consistent with that of observed SLP change showing positive trends over the Maritime Continent and negative trends over the central equatorial Pacific. Suppressed moisture convergence over the Maritime Continent is largely due to surface wind changes, contributing to observed decreases in marine cloudiness and land precipitation there. Furthermore, observed ocean mixed layer temperatures indicate a reduction in zonal contrast in the tropical Indo-Pacific characterized by larger warming in the tropical eastern Pacific and western Indian Ocean than in the tropical western Pacific and eastern Indian Ocean. Similar changes are successfully simulated by an ocean general circulation model forced with the bias-corrected wind stress. Whereas results from major SST reconstructions show large uncertainty in zonal gradient in the tropical Indo-Pacific, both bucket-sampled SSTs and nighttime marine air temperatures show a weakening of the zonal gradient consistent with the subsurface temperature changes. All these findings from independent observations provide robust evidence for ocean-atmosphere coupling associated with the reduction in the Walker circulation over the last six decades.
Atmospheric changes through 2012 as shown by iteratively homogenized radiosonde temperature and wind data (IUKv2)
NASA Astrophysics Data System (ADS)
Sherwood, Steven C.; Nishant, Nidhi
We present an updated version of the radiosonde dataset homogenized by Iterative Universal Kriging (IUKv2), now extended through February 2013, following the method used in the original version (Sherwood et al 2008 Robust tropospheric warming revealed by iteratively homogenized radiosonde data J. Clim. 21 5336�52). This method, in effect, performs a multiple linear regression of the data onto a structural model that includes both natural variability, trends, and time-changing instrument biases, thereby avoiding estimation biases inherent in traditional homogenization methods. One modification now enables homogenized winds to be provided for the first time. This, and several other small modifications made to the original method sometimes affect results at individual stations, but do not strongly affect broad-scale temperature trends. Temperature trends in the updated data show three noteworthy features. First, tropical warming is equally strong over both the 1959�2012 and 1979�2012 periods, increasing smoothly and almost moist-adiabatically from the surface (where it is roughly 0.14 K/decade) to 300 hPa (where it is about 0.25 K/decade over both periods), a pattern very close to that in climate model predictions. This contradicts suggestions that atmospheric warming has slowed in recent decades or that it has not kept up with that at the surface. Second, as shown in previous studies, tropospheric warming does not reach quite as high in the tropics and subtropics as predicted in typical models. Third, cooling has slackened in the stratosphere such that linear trends since 1979 are about half as strong as reported earlier for shorter periods. Wind trends over the period 1979�2012 confirm a strengthening, lifting and poleward shift of both subtropical westerly jets; the Northern one shows more displacement and the southern more intensification, but these details appear sensitive to the time period analysed. There is also a trend toward more easterly winds in the middle and upper troposphere of the deep tropics.
Agents of change on Mars' northern dunes: CO2 ice and wind
NASA Astrophysics Data System (ADS)
Hansen, C. J.; Diniega, S.; Bridges, N.; Byrne, S.; Dundas, C.; McEwen, A.; Portyankina, G.
Both wind and seasonal CO2 ice sculpt the dunes of Mars in today's climate. The High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter has returned extensive temporal coverage of changes on the north polar dunes for nearly four Mars years. The processes driving dune morphology changes such as the formation of new alcoves have been investigated. Considerable interannual variability has been observed. Most changes occur in the period of time when HiRISE cannot image: late summer and fall when light levels are too low to see subtle changes on the dunes and the polar hood obscures the surface, and winter when the cap is in polar night. This is consistent with seasonal control but does not allow us to directly differentiate between eolian processes vs. CO2 ice as the driving agent for alcove formation. Circumstantial evidence and observations of analog processes in the southern mid-latitudes however implicates processes associated with frost emplacement and removal.
Solar-wind-driven changes to the ionospheric electric potential lead to changes in tropospheric temperature and geopotential height
NASA Astrophysics Data System (ADS)
Lam, Mai Mai; Chisham, Gareth; Freeman, Mervyn P.
There are a large number of responses, on the day-to-day timescale, of the dynamics of the troposphere to regional changes in the downward current of the global atmospheric electric circuit (GEC). They provide compelling evidence that, via the GEC, the solar wind plays a role in influencing surface weather and climate. We use reanalysis data to estimate the altitude and time lag dependence of one such response - the Mansurov effect. This effect was first observed as a correlation between the duskward component By of the interplanetary magnetic field (IMF) and surface pressure anomalies in Antarctica. Additionally, we have more recently shown that the polar Mansurov effect can affect mid-latitude atmospheric planetary waves, the amplitude of the effect being comparable to typical initial analysis uncertainties in ensemble numerical weather prediction. Here we shed light on the origins of the polar surface effect by examining the correlation between IMF By and geopotential height anomalies throughout the Antarctic troposphere and lower stratosphere. We find that the correlation is highly statistically significant within the troposphere, and not so in the stratosphere. The peak in the correlation occurs at greater time lags at the tropopause (~ 6 - 8 days) and in the mid troposphere (~ 4 days) than in the lower troposphere (~ 1 day). This supports a mechanism involving the action on lower tropospheric clouds of the GEC, modified by variations in the solar wind (through modulations of the spatial variation in ionospheric potential). The increase in time lag with increasing altitude is consistent with the upward propagation by conventional atmospheric processes of the solar wind-induced variability in the lower troposphere. This is in contrast to the downward propagation of atmospheric effects to the lower troposphere from the stratosphere due to solar variability-driven mechanisms involving ultraviolet radiation or energetic particle precipitation. We also find a correlation between IMF By and the tropospheric air temperature anomaly, which is of lower statistical significance than the geopotential height effect described above. Up to altitudes of 3 km, the anomalies in air temperature are related to the geopotential height by the environmental lapse rate, and therefore considered to be real and to be part of the Mansurov effect. The mean air temperature anomaly across Antarctica associated with the Mansurov effect is up to 0.8 K.
Control of finger force vectors with changes in fingertip referent coordinates
Wu, Yen-Hsun; Zatsiorsky, Vladimir M.; Latash, Mark L.
The central hypothesis explored in the experiment is that adjustments of fingertip force vectors during object manipulation could result from a simple scaling rule applied to commands to individual digits. The commands have been associated with referent coordinates of the digit tips. The subjects performed quick lifting movements (over 20 cm in under 0.5 s) of a horizontally oriented handle with different combinations of the external load and torque. The prismatic grasp was used with the four fingers pressing on the bottom of the handle and the thumb acting on its top. Principal component and correlation analyses applied to the normal and tangential force vector components confirmed that the force direction of each digit was kept nearly constant in the object-centered referent frame across the loading conditions and movement phases. The middle and ring fingers showed weaker correlations between the force components as compared to the index and little fingers. The differences were likely related to the different roles of the normal force components in the moment of force production. The neural control of the hand, within the studied task, may be adequately described as a simple rule applied to a handful of parameters, such as the referent digit-tip coordinates. PMID:23394398
Impact of climate change upon vector born diseases in Europe and Africa using ENSEMBLES Regional Climate Models
NASA Astrophysics Data System (ADS)
Caminade, Cyril; Morse, Andy
Climate variability is an important component in determining the incidence of a number of diseases with significant human/animal health and socioeconomic impacts. The most important diseases affecting health are vector-borne, such as malaria, Rift Valley Fever and including those that are tick borne, with over 3 billion of the world population at risk. Malaria alone is responsible for at least one million deaths annually, with 80% of malaria deaths occurring in sub-Saharan Africa. The climate has a large impact upon the incidence of vector-borne diseases; directly via the development rates and survival of both the pathogen and the vector, and indirectly through changes in the environmental conditions. A large ensemble of regional climate model simulations has been produced within the ENSEMBLES project framework for both the European and African continent. This work will present recent progress in human and animal disease modelling, based on high resolution climate observations and regional climate simulations. Preliminary results will be given as an illustration, including the impact of climate change upon bluetongue (disease affecting the cattle) over Europe and upon malaria and Rift Valley Fever over Africa. Malaria scenarios based on RCM ensemble simulations have been produced for West Africa. These simulations have been carried out using the Liverpool Malaria Model. Future projections highlight that the malaria incidence decreases at the northern edge of the Sahel and that the epidemic belt is shifted southward in autumn. This could lead to significant public health problems in the future as the demography is expected to dramatically rise over Africa for the 21st century.
Wind Characterization for the Assessment of Collision Risk During Flight Level Changes
NASA Technical Reports Server (NTRS)
Carreno, Victor; Chartrand, Ryan
A model of vertical wind gradient is presented based on National Oceanic and Atmospheric Administration (NOAA) wind data. The objective is to have an accurate representation of wind to be used in Collision Risk Models (CRM) of aircraft procedures. Depending on how an aircraft procedure is defined, wind and the different characteristics of the wind will have a more severe or less severe impact on distances between aircraft. For the In-Trail Procedure, the non-linearity of the vertical wind gradient has the greatest impact on longitudinal distance. The analysis in this paper extracts standard deviation, mean, maximum, and linearity characteristics from the NOAA data.
Impact of WRF Physics and Grid Resolution on Low-level Wind Prediction: Towards the Assessment of Climate Change Impact on Future Wind Power
Chin, H S; Glascoe, L; Lundquist, J; Wharton, S
The Weather Research and Forecast (WRF) model is used in short-range simulations to explore the sensitivity of model physics and horizontal grid resolution. We choose five events with the clear-sky conditions to study the impact of different planetary boundary layer (PBL), surface and soil-layer physics on low-level wind forecast for two wind farms; one in California (CA) and the other in Texas (TX). Short-range simulations are validated with field measurements. Results indicate that the forecast error of the CA case decreases with increasing grid resolution due to the improved representation of valley winds. Besides, the model physics configuration has a significant impact on the forecast error at this location. In contrast, the forecast error of the TX case exhibits little dependence on grid resolution and is relatively independent of physics configuration. Therefore, the occurrence frequency of lowest root mean square errors (RMSEs) at this location is used to determine an optimal model configuration for subsequent decade-scale regional climate model (RCM) simulations. In this study, we perform two sets of 20-year RCM simulations using the data from the NCAR Global Climate Model (GCM) simulations; one set models the present climate and the other simulates the future climate. These RCM simulations will be used to assess the impact of climate change on future wind energy.
Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)
NASA Astrophysics Data System (ADS)
Erickson, R. A.; Hayhoe, K.; Presley, S. M.; Allen, L. J. S.; Long, K. R.; Cox, S. B.
Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems.
Vector Fields. Winding Number and Index. Poincare Theorem. Alexander Belyaev (firstname.lastname@example.com, http://www.mpi-sb.mpg.de/belyaev)
Christensen, Dan
as the velocity of some substance (for example, water) moving inside D. Placement of the vector V (P) with its tail at P helps to visualize the vector field. For practical purposes it is usually more convenient, such as the pressure gradient on a weather map or the height gradient of a relief chart, are vector fields. Vector
National Assessment of Shoreline Change: A GIS compilation of vector shorelines and associated shoreline change data for the sandy shorelines of Kauai, Oahu, and Maui, Hawaii
Romine, Bradley M.; Fletcher, Charles H.; Genz, Ayesha S.; Barbee, Matthew M.; Dyer, Matthew; Anderson, Tiffany R.; Lim, S. Chyn; Vitousek, Sean; Bochicchio, Christopher; Richmond, Bruce M.
Sandy ocean beaches are a popular recreational destination, and often are surrounded by communities that consist of valuable real estate. Development is increasing despite the fact that coastal infrastructure may be repeatedly subjected to flooding and erosion. As a result, the demand for accurate information regarding past and present shoreline changes is increasing. Working with researchers from the University of Hawaii, investigators with the U.S. Geological Survey's National Assessment of Shoreline Change Project have compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the islands of Kauai, Oahu, and Maui, Hawaii. No widely accepted standard for analyzing shoreline change currently exists. Current measurement and rate-calculation methods vary from study to study, precluding the combination of study results into statewide or regional assessments. The impetus behind the National Assessment was to develop a standardized method for measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the measurements in an internally consistent manner. A detailed report on shoreline change for Kauai, Maui, and Oahu that contains a discussion of the data presented here is available and cited in the Geospatial Data section of this report.
Impact of Global Climate Changes on the Wind Power Density in Brazil
Fernando Martins; Enio Pereira; Marcelo Pes; Eliude Segundo; Andr Lyra
The potential onshore wind power resources in Brazil could reach more than 145,000 MW. Brazil's wind energy production has risen up from 22 MW in 2003 to 602 MW in 2009 thanks to the government policy and incentives to encourage the use of wind power and other renewable sources of energy. An additional 256.4 MW is now under construction and
Changes in fluxes of heat, H2O, CO2 caused by a large wind farm
Technology Transfer Automated Retrieval System (TEKTRAN)
The Crop Wind Energy Experiment (CWEX) provides a platform to investigate the effect of wind turbines and large wind farms on surface fluxes of momentum, heat, moisture and carbon dioxide (CO2). In 2010 and 2011, eddy covariance flux stations were installed between two lines of turbines at the south...
The National Assessment of Shoreline Change:A GIS Compilation of Vector Shorelines and Associated Shoreline Change Data for the Sandy Shorelines of the California Coast
Hapke, Cheryl J.; Reid, David
Introduction The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector shorelines and shoreline change rates for the sandy shoreline along the California open coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, and internally consistent updates of shorelines and shoreline change rates can be made at a National Scale. This data compilation for open-ocean, sandy shorelines of the California coast is one in a series that already includes the Gulf of Mexico and the Southeast Atlantic Coast (Morton et al., 2004; Morton et al., 2005) and will eventually cover Washington, Oregon, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are determined by comparing the positions of three historical shorelines digitized from maps, with a modern shoreline derived from LIDAR (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time-periods: 1850s-1880s, 1920s-1930s, and late 1940s-1970s. The most recent shoreline is from data collected between 1997 and 2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change of the California coastline at http://pubs.usgs.gov/of/2006/1219/ for additional information regarding methods and results (Hapke et al., 2006). Data in this report are organized into downloadable layers by region (Northern, Central and Southern California) and are provided as vector datasets with metadata. Vector shorelines may represent a compilation of data from one or more sources and these sources are included in the dataset metadata. This project employs the Environmental Systems Research Institute's (ESRI) ArcGIS as it's GIS mapping tool and contains several data layers (shapefiles) that are used to create a geographic view of the California Coast. These vector data form a basemap comprised of polygon and line themes that include a U.S. coastline (1:80,000), U.S. cities, and state boundaries.
Petrie, G. J. D. [National Solar Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
We analyze the spatial and temporal variations of the abrupt photospheric magnetic changes associated with six major flares using 12 minute, 0.''5 pixel{sup -1} vector magnetograms from NASA's Helioseismic and Magnetic Imager instrument on the Solar Dynamics Observatory satellite. The six major flares occurred near the main magnetic neutral lines of four active regions, NOAA 11158, 11166, 11283, and 11429. During all six flares the neutral-line field vectors became stronger and more horizontal, in each case almost entirely due to strengthening of the horizontal field components parallel to the neutral line. In all six cases the neutral-line pre-flare fields were more vertical than the reference potential fields, and collapsed abruptly and permanently closer to potential-field tilt angles during every flare, implying that the relaxation of magnetic stress associated with non-potential tilt angles plays a major role during major flares. The shear angle with respect to the reference potential field did not show such a pattern, demonstrating that flare processes do not generally relieve magnetic stresses associated with photospheric magnetic shear. The horizontal fields became significantly and permanently more aligned with the neutral line during the four largest flares, suggesting that the collapsing field is on average more aligned with the neutral line than the pre-flare neutral-line field. The vertical Lorentz force had a large, abrupt, permanent downward change during each of the flares, consistent with loop collapse. The horizontal Lorentz force changes acted mostly parallel to the neutral line in opposite directions on each side, a signature of the fields contracting during the flare, pulling the two sides of the neutral line toward each other. The greater effect of the flares on field tilt than on shear may be explained by photospheric line-tying.
Massachusetts shoreline change project: a GIS compilation of vector shorelines and associated shoreline change data for the 2013 update
Smith, Theresa L.; Himmelstoss, Emily A.; Thieler, E. Robert
Identifying the rates and trends associated with the position of the shoreline through time presents vital information on potential impacts these changes may have on coastal populations and infrastructure, and supports informed coastal management decisions. This report publishes the historical shoreline data used to assess the scale and timing of erosion and accretion along the Massachusetts coast from New Hampshire to Rhode Island including all of Cape Cod, Martha�s Vineyard, Nantucket and the Elizabeth Islands. This data is an update to the Massachusetts Office of Coastal Zone Management Shoreline Change Project. Shoreline positions from the past 164 years (1845 to 2009) were used to compute the shoreline change rates. These data include a combined length of 1,804 kilometers of new shoreline data derived from color orthophoto imagery collected in 2008 and 2009, and topographic lidar collected in 2007. These new shorelines have been added to previously published historic shoreline data from the Massachusetts Office of Coastal Zone Management and the U.S. Geological Survey. A detailed report containing a discussion of the shoreline change data presented here and a summary of the resulting rates is available and cited at the end of the Introduction section of this report.
Wind power or uranium mine: Appraisal of two energy-related environmental changes in a local context
Eja Pedersen; Maria Johansson
This study explores factors associated with the individual's appraisal of anticipated environmental changes caused by energy production facilities. The study took place in a Swedish village where exploratory drilling, that could eventually lead to a uranium mine, was being conducted at the same time as a wind farm was approved. Results from the survey, which included the total population, were
Long-term changes in solar wind elemental and isotopic ratios: A compairosn of two lunar ilmenites of different antiquities
Becker, R.H.; Pepin, R.O. (Univ. of Minneapolis, MN (USA))
An ilmenite separate from lunar regolith breccia 79035, a sample presumed to have been exposed to solar wind more than 2 Ga ago, was analyzed for noble gas and nitrogen elemental and isotopic abundances by stepwise oxidation and pyrolysis. The gases appear to be distributed between two distinct reservoirs in the ilmenite, defined by release patterns and isotopic considerations. One of the reservoirs, near grain surfaces, yields elemental ratios that for the most part are solar while the other, sited at greater depths within grains, has severely fractionated elemental abundances and generally heavier isotopic ratios as well. Xenon provides an exception to the solar abundance pattern in the near-surface reservoir, being enhanced by about a factor of 2 relative to the expected value. A comparison of the 79035 separate with a previously analyzed ilmenite from soil 71501, which received its solar wind exposure much more recently, indicates that the two-fold xenon enhancement occurs in the fractionated reservoir as well as the solar one, and that it may therefore be attributable to a change in the solar wind elemental abundances. Other differences between the two ilmenites occur in helium and neon isotopic ratios and in He/Ar elemental ratios. Since mineralogical influences on retentivities of the gases in the two samples should be the same, and possible contributions of non-solar wind components to one ilmenite in preference to the other can generally be eliminated or accounted for, all of these differences may reflect changes in the solar wind over time.
Changes in vector species composition and current vector biology and behaviour will favour malaria elimination in Santa Isabel Province, Solomon Islands
Background In 2009, Santa Isabel Province in the Solomon Islands embarked on a malaria elimination programme. However, very little is known in the Province about the anopheline fauna, which species are vectors, their bionomics and how they may respond to intensified intervention measures. The purpose of this study was to provide baseline data on the malaria vectors and to ascertain the possibility of successfully eliminating malaria using the existing conventional vector control measures, such as indoor residual spraying (IRS) and long-lasting insecticidal nets (LLIN). Methods Entomological surveys were undertaken during October 2009. To determine species composition and distribution larval surveys were conducted across on the whole island. For malaria transmission studies, adult anophelines were sampled using human landing catches from two villages - one coastal and one inland. Results Five Anopheles species were found on Santa Isabel: Anopheles farauti, Anopheles hinesorum, Anopheles lungae, Anopheles solomonis, and Anopheles nataliae. Anopheles hinesorum was the most widespread species. Anopheles farauti was abundant, but found only on the coast. Anopheles punctulatus and Anopheles koliensis were not found. Anopheles farauti was the only species found biting in the coastal village, it was incriminated as a vector in this study; it fed early in the night but equally so indoors and outdoors, and had a low survival rate. Anopheles solomonis was the main species biting humans in the inland village, it was extremely exophagic, with low survival rates, and readily fed on pigs. Conclusion The disappearance of the two major vectors, An. punctulatus and An. koliensis, from Santa Isabel and the predominance of An. hinesorum, a non-vector species may facilitate malaria elimination measures. Anopheles farauti was identified as the main coastal vector with An. solomonis as a possible inland vector. The behaviour of An. solomonis is novel as it has not been previously found biting humans in any numbers. Both species appear to be short-lived, a characteristic that will limit their transmission potential. The early night feeding behaviour and a degree of outdoor biting seen in An. farauti and particularly in An. solomonis will require that their response to IRS and LLIN be closely monitored. In coastal villages, where large, favourable breeding sites allow for high numbers of An. farauti may require the addition of larval control to achieve elimination. PMID:21961990
A century of glacier change in the Wind River Range, WY
NASA Astrophysics Data System (ADS)
DeVisser, Mark H.; Fountain, Andrew G.
The Wind River Range spans roughly 200 km along the continental divide in western Wyoming and encompasses at least 269 glaciers and perennial snowfields totaling 34.34 � 0.13 km2 (2006), including Gannett Glacier, the largest glacier (2.81 km2) in the continental U.S. outside of Washington State. To track changing glacier and perennial snow surface area over the past century we used historic maps, aerial photography, and geologic evidence evident in said imagery. Since the end of the Little Ice Age (~ 1900), when the glaciers retreated from their moraines, to 2006 the ice-covered area shrank by ~ 47%. The main driver of surface area change was air temperature, with glaciers at lower elevations shrinking faster than those at higher elevations. The total contribution of ice wastage to late summer stream flow ranged from 0.4 to 1.5%, 0.9 to 2.8%, 1.7 to 5.4%, and 3.4 to 10.9% in four different watersheds, none of which exceeded 7% glacier cover. Results from previous studies were difficult to include because of differences in interpretation of glacier boundaries, because of poor imagery, or to extensive seasonal snow. These difficulties highlight potential problems in combining data sets from different studies and underscores the importance of reexamining past observations to ensure consistent interpretation.
KITANO M. and EGUCHI H. Dynamics of whole plant water balance and leaf growth in response to evaporative demand. II. Effect of change in wind velocity. BIOTRONICS 21, 51-60, 1992. Dynamics of whole plant water balance and leaf expansive growth were analyzed in cucumber plants (Cucumis sativus L.) exposed to step change in wind velocity (U). The effect of step
Potential impacts of topography and prevailing wind direction on future precipitation changes in Japan
NASA Astrophysics Data System (ADS)
Tsunematsu, N.; Dairaku, K.; Hirano, J.
To investigate future changes in summertime precipitation amounts over the Japanese islands and their relations to the topographical heights, this study analyzed 20 km horizontal grid-spacing regional climate model downscalings of MIROC3.2-hires 20C3M and SRES-A1B scenario data for the periods of 1981-2000 and 2081-2100. Results indicate the remarkable increases in June-July-August mean daily precipitation in the west and south sides (windward sides) of the mountainous regions, especially in western Japan where heavy rainfall is frequently observed in the recent climate. The remarkable increases in summertime precipitation are likely to occur not only in high altitude areas but also at low altitudes. The occurrence frequencies of precipitation greater than 100 mm/day would also increase in such areas. The intensification of southwesterly moist air flows in the lower troposphere is considered to be one of the main causes of those precipitation changes because the intensified southwesterly moist air flows impinging on the western and southern slopes of the mountains can generate stronger upslope flows and well-developed clouds, leading to increased precipitation. Also, the results show that future precipitation changes in the lee sides of the mountainous regions (e.g., the Tokyo metropolitan area) would be comparatively small. These results indicate large influences of topography and prevailing wind direction on future precipitation changes. Acknowledgments: This study was conducted as part of the research subject "Vulnerability and Adaptation to Climate Change in Water Hazard Assessed Using Regional Climate Scenarios in the Tokyo Region' (National Research Institute for Earth Science and Disaster Prevention; PI: Koji Dairaku) of Research Program on Climate Change Adaptation (RECCA) and was supported by the SOUSEI Program, funded by Ministry of Education, Culture, Sports, Science and Technology, Government of Japan. We thank the regional climate modeling groups (MRI/NIED/Univ. Tsukuba) for producing and making available their model output. Their work was supported by the Environment Research and Technology Development Fund (S5-3) of the Ministry of the Environment, Japan.
Climate and Population Health Vulnerabilities to Vector-Borne Diseases: Increasing Resilience Under Climate Change Conditions in Africa
NASA Astrophysics Data System (ADS)
Ceccato, P.; McDonald, K. C.; Podest, E.; De La Torre Juarez, M.; Kruczkiewicz, A.; Lessel, J.; Jensen, K.; Thomson, M. C.
The International Research Institute for Climate and Society (IRI), the City University of New York (CUNY) and NASA Jet Propulsion Laboratory (JPL) in collaboration with NASA SERVIR are developing tools to monitor climate variables (precipitation, temperature, vegetation, water bodies, inundation) that help projects in Africa to increase resilience to climate change for vector-borne diseases (i.e. malaria, trypanosomiasis, leishmaniasis, and schistosomiasis). Through the development of new products to monitor precipitation, water bodies and inundation, IRI, CUNY and JPL provide tools and capacity building to research communities, ministries of health and World Health Organization in Africa to: 1) Develop research teams' ability to appropriately use climate data as part of their research 2) Enable research teams and ministries to integrate climate information into social and economic drivers of vulnerability and opportunities for adaptation to climate change 3) Inform better policies and programs for climate change adaptation. This oral presentation will demonstrate how IRI, CUNY, and JPL developed new products, tools and capacity building to achieve the three objectives mentioned above.
Population genetics of two key mosquito vectors of rift valley Fever virus reveals new insights into the changing disease outbreak patterns in kenya.
Tchouassi, David P; Bastos, Armanda D S; Sole, Catherine L; Diallo, Mawlouth; Lutomiah, Joel; Mutisya, James; Mulwa, Francis; Borgemeister, Christian; Sang, Rosemary; Torto, Baldwyn
Rift Valley fever (RVF) outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi) and newly-associated (Ae. ochraceus) vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification. PMID:25474018
The trophic responses of two different rodent-vector-plague systems to climate change.
Xu, Lei; Schmid, Boris V; Liu, Jun; Si, Xiaoyan; Stenseth, Nils Chr; Zhang, Zhibin
Plague, the causative agent of three devastating pandemics in history, is currently a re-emerging disease, probably due to climate change and other anthropogenic changes. Without understanding the response of plague systems to anthropogenic or climate changes in their trophic web, it is unfeasible to effectively predict years with high risks of plague outbreak, hampering our ability for effective prevention and control of the disease. Here, by using surveillance data, we apply structural equation modelling to reveal the drivers of plague prevalence in two very different rodent systems: those of the solitary Daurian ground squirrel and the social Mongolian gerbil. We show that plague prevalence in the Daurian ground squirrel is not detectably related to its trophic web, and that therefore surveillance efforts should focus on detecting plague directly in this ecosystem. On the other hand, plague in the Mongolian gerbil is strongly embedded in a complex, yet understandable trophic web of climate, vegetation, and rodent and flea densities, making the ecosystem suitable for more sophisticated low-cost surveillance practices, such as remote sensing. As for the trophic webs of the two rodent species, we find that increased vegetation is positively associated with higher temperatures and precipitation for both ecosystems. We furthermore find a positive association between vegetation and ground squirrel density, yet a negative association between vegetation and gerbil density. Our study thus shows how past surveillance records can be used to design and improve existing plague prevention and control measures, by tailoring them to individual plague foci. Such measures are indeed highly needed under present conditions with prevailing climate change. PMID:25540277
Late-glacial to holocene changes in winds, upwelling, and seasonal production of the northern California current system
Sancetta, C.; Lyle, M.; Heusser, L.; Zahn, R.; Bradbury, J.P.
A core 120 km off the coast of southern Oregon was examined for changes in lithology, diatoms, and pollen over the past 30,000 yr. Primary production during the late Pleistocene was about half that of the Holocene. Evidence from diatoms and pollen indicates that summer upwelling was much weaker, implying an absence of strong northerly winds. Early Pliocene diatoms found throughout the late Pleistocene section were probably derived from diatomites east of the Cascades and provide evidence for strong easterly winds over a dry continental interior. The findings verify predictions of a climate model based on glacial maximum conditions. There is no compelling evidence for a climatic reversal corresponding to the European Younger Dryas chron. During the early Holocene (9000-7000 yr B.P.) there may have been years when winds were insufficiently strong to support upwelling, so that warm stratified waters lay closer to the coast. ?? 1992.
Statistical-dynamical downscaling for wind energy potentials: Evaluation and applications to decadal hindcasts and climate change projections
NASA Astrophysics Data System (ADS)
Reyers, Mark; Pinto, Joaquim G.; Moemken, Julia
A statistical-dynamical downscaling (SDD) approach for the regionalisation of wind energy output (Eout) over Europe with special focus on Germany is proposed. SDD uses an extended circulation weather type (CWT) analysis on global daily MSLP fields with the central point being located over Germany. 77 weather classes based on the associated circulation weather type and the intensity of the geostrophic flow are identified. Representatives of these classes are dynamical downscaled with the regional climate model COSMO-CLM. By using weather class frequencies of different datasets the simulated representatives are recombined to probability density functions (PDFs) of near-surface wind speed and finally to Eout of a sample wind turbine for present and future climate. This is performed for reanalysis, decadal hindcasts and long-term future projections. For evaluation purposes results of SDD are compared to wind observations and to simulated Eout of purely dynamical downscaling (DD) methods. For the present climate SDD is able to simulate realistic PDFs of 10m-wind speed for most stations in Germany. The resulting spatial Eout patterns are similar to DD simulated Eout. In terms of decadal hindcasts results of SDD are similar to DD simulated Eout over Germany, Poland, Czech Republic, and Benelux, for which high correlations between annual Eout timeseries of SDD and DD are detected for selected hindcasts. Lower correlation is found for other European countries. It is demonstrated that SDD can be used to downscale the full ensemble of the MPI-ESM decadal prediction system. Long-term climate change projections in SRES scenarios of ECHAM5/MPI-OM as obtained by SDD agree well to results of other studies using DD methods, with increasing Eout over Northern Europe and a negative trend over Southern Europe. Despite some biases it is concluded that SDD is an adequate tool to assess regional wind energy changes in large model ensembles.
Assessing climate change impacts on the near-term stability of the wind energy
Pryor, Sara C.
wind power are being increasingly harnessed to provide electricity generation potential with negligi energy electricity generation capacity was added worldwide during 2007 and 2008 (3), which accounted the last five years have more than doubled wind-derived electricity generation capacity (2) to over 40 GW
Pharmacological analysis of calcium transients in response to gravity vector change in Arabidopsis hypocotyls and petioles.
NASA Astrophysics Data System (ADS)
Toyota, M.; Furuichi, T.; Tatsumi, H.; Sokabe, M.
Plants regulate their growth and morphology in response to gravity field known as gravitropism in general In the process of gravitropism gravity sensing will form the critical earliest event which is supposed to take place in specialized cells statocytes such as columella cells and shoot endodermal cells Although gravistimulation is assumed to be converted into certain intracellular signals the underlying transduction mechanisms have hardly been explored One of the potential candidates for the intracellular signals is an increase in the cytoplasmic free calcium concentration Ca 2 c Here we measured Ca 2 c changes induced by gravistimulation in seedlings of Arabidopsis thaliana expressing aequorin as a calcium reporter When a plate of seedlings was turned through 180 r Ca 2 c transiently increased within 50 s and decayed exponentially with a time constant of ca 60 s The amplitude of the Ca 2 c increase was independent of the angular velocity of the rotation The Ca 2 c increase was reversibly blocked by extracellularly applied potential mechanosensitive channel blockers La 3 Gd 3 or a Ca 2 chelator BAPTA indicating that it arose from Ca 2 -influx via Ca 2 -permeable channel s on the plasma membrane Furthermore the Ca 2 c increase was attenuated by actin-disrupting drugs latrunculin B cytochalasin B but not by microtuble-disrupting drugs oryzalin nocodazole indicating that the activation of
Analysis of change in the wind speed ratio according to apartment layout and solutions.
Hyung, Won-gil; Kim, Young-Moon; You, Ki-Pyo
Apartment complexes in various forms are built in downtown areas. The arrangement of an apartment complex has great influence on the wind flow inside it. There are issues of residents' walking due to gust occurrence within apartment complexes, problems with pollutant emission due to airflow congestion, and heat island and cool island phenomena in apartment complexes. Currently, the forms of internal arrangements of apartment complexes are divided into the flat type and the tower type. In the present study, a wind tunnel experiment and computational fluid dynamics (CFD) simulation were performed with respect to internal wind flows in different apartment arrangement forms. Findings of the wind tunnel experiment showed that the internal form and arrangement of an apartment complex had significant influence on its internal airflow. The wind velocity of the buildings increased by 80% at maximum due to the proximity effects between the buildings. The CFD simulation for relaxing such wind flows indicated that the wind velocity reduced by 40% or more at maximum when the paths between the lateral sides of the buildings were extended. PMID:24688430
Changing Malaria Prevalence on the Kenyan Coast since 1974: Climate, Drugs and Vector Control
Snow, Robert W.; Kibuchi, Eliud; Karuri, Stella W.; Sang, Gilbert; Gitonga, Caroline W.; Mwandawiro, Charles; Bejon, Philip; Noor, Abdisalan M.
Background Progress toward reducing the malaria burden in Africa has been measured, or modeled, using datasets with relatively short time-windows. These restricted temporal analyses may miss the wider context of longer-term cycles of malaria risk and hence may lead to incorrect inferences regarding the impact of intervention. Methods 1147 age-corrected Plasmodium falciparum parasite prevalence (PfPR2-10) surveys among rural communities along the Kenyan coast were assembled from 1974 to 2014. A Bayesian conditional autoregressive generalized linear mixed model was used to interpolate to 279 small areas for each of the 41 years since 1974. Best-fit polynomial splined curves of changing PfPR2-10 were compared to a sequence of plausible explanatory variables related to rainfall, drug resistance and insecticide-treated bed net (ITN) use. Results P. falciparum parasite prevalence initially rose from 1974 to 1987, dipped in 1991�92 but remained high until 1998. From 1998 onwards prevalence began to decline until 2011, then began to rise through to 2014. This major decline occurred before ITNs were widely distributed and variation in rainfall coincided with some, but not all, short-term transmission cycles. Emerging resistance to chloroquine and introduction of sulfadoxine/pyrimethamine provided plausible explanations for the rise and fall of malaria transmission along the Kenyan coast. Conclusions Progress towards elimination might not be as predictable as we would like, where natural and extrinsic cycles of transmission confound evaluations of the effect of interventions. Deciding where a country lies on an elimination pathway requires careful empiric observation of the long-term epidemiology of malaria transmission. PMID:26107772
Ground winds and winds aloft Edwards AFB, California
NASA Technical Reports Server (NTRS)
Johnson, D. L.; Brown, S. C.
Ground level runway wind statistics cover crosswind, tailwind, and headwind reversal percentage frequencies with respect to month and hour for the two major runways. Also presented are bivariate normal wind statistics for a 90 degree flight azimuth for altitudes 0 through 27 km. Wind probability distributions, synthetic vector wind profiles, and statistics for any rotation of axes are computed from five given parameters.
Clothing ventilation, vapour resistance and permeability index: changes due to posture, movement and wind
Using the trace gas diffusion method, the vapour resistance of three clothing ensembles (two permeable and one impermeable) was determined for four subjects, sitting, standing or walking at 0-3 and 09 m\\/s, combined with three wind speeds of <0-15, 0-7 and 41 m\\/s. Sitting increased vapour resistance by 12-36%, whereas walking and wind decreased the resistance by 72% and 89%
Motion of the dusk flank boundary layer caused by solar wind pressure changes and the Kelvin-Helmholtz instability: 10�11 January 1997
D. H. Fairfield; C. J. Farrugia; T. Mukai; T. Nagai; A. Fedorov
During an interval of steady northward IMF on 10�11 January 1997, Geotail and Interball spacecraft data at X = ?5 to ?15 RE on the dusk flank reveal magnetopause boundary layer motions caused by both solar wind pressure discontinuities and the Kelvin-Helmholtz instability. Several large, sudden changes in solar wind density caused the magnetopause to move across both spacecraft. Relative
Combined Wind Vector and Sea State Impact on Ocean Nadir-Viewing Ku- and C-Band Radar Cross-Sections
Tran, Ngan; Chapron, Bertrand
The authors report the first results in studying the polarization anisotropy of the microwave backscatter from nadir observations provided by Jason-1 altimeter in both Ku- and C-band. A small but clear wind direction signal for wind speeds above 6 m/s is revealed. These azimuthal variations of radar cross-section increase with increasing wind speed up to 14 m/s. The signatures then level off at higher winds. These results extend, for the first time, recent theoretical improved scattering approximation, and point some similarities between scattering and emission mechanisms at nadir. The observed directional effect can thus be interpreted as a signature of the curvature anisotropy of wind-generated short-scale waves. Sensitivities to both wind speed and sea state are also reported in the present analysis.
Future changes of wind energy potentials over Europe in a large CMIP5 multi-model ensemble
NASA Astrophysics Data System (ADS)
Reyers, Mark; Moemken, Julia; Pinto, Joaquim G.
A statistical-dynamical downscaling method is used to estimate future changes of wind energy output (Eout) of an idealized wind turbine across Europe at the regional scale. With this aim, 22 GCMs of the CMIP5 ensemble are considered. The downscaling method uses circulation weather types and regional climate modelling with the COSMO-CLM model. Future projections are computed for two time periods (2021-2060 and 2061-2100) following two scenarios (RCP4.5 and RCP8.5). The CMIP5 ensemble mean response reveal a more likely than not increase of mean annual Eout over Northern and Central Europe and a likely decrease over Southern Europe. There is some uncertainty with respect to the magnitude and the sign of the changes. Higher robustness in future changes is observed for specific seasons. Except from the Mediterranean area, an ensemble mean increase of Eout is simulated for winter and a decreasing for the summer season, resulting in a strong increase of the intra-annual variability for most of Europe. The latter is in particular likely during the 2nd half of the 21st century under the RCP8.5 scenario. In general, signals are stronger for 2061-2100 compared to 2021-2060 and for RCP8.5 compared to RCP4.5. Regarding changes of the inter-annual variability of Eout for Central Europe, the future projections strongly vary between individual models and also between future periods and scenarios within single models. This study showed for an ensemble of 22 CMIP5 models that changes in the wind energy potentials over Europe may take place in future decades. However, due to the uncertainties detected in this research, further investigations with multi-model ensembles are needed to provide a better quantification and understanding of the future changes.
Spatial and temporal changes in Lutzomyia longipalpis abundance, a Leishmania infantum vector in an urban area in northeastern Argentina
Fern�ndez, Mar�a Soledad; Santini, Mar�a Soledad; Cavia, Regino; Sandoval, Adolfo Enrique; P�rez, Adriana Alicia; Acardi, Soraya; Salom�n, Oscar Daniel
This study aimed to analyse changes in the spatial distribution of Lutzomyia longipalpis in Posadas, an urban area located in northeastern Argentina. Data were obtained during the summer of 2007 and 2009 through two entomological surveys of peridomiciles distributed around the city. The abundance distribution pattern for 2009 was computed and compared with the previous pattern obtained in 2007, when the first human visceral leishmaniasis cases were reported in the city. Vector abundance was also examined in relation to micro and macrohabitat characteristics. In 2007 and 2009, Lu. longipalpis was distributed among 41.5% and 31% of the households in the study area, respectively. In both years, the abundance rates at most of the trapping sites were below 30 Lu. longipalpis per trap per night; however, for areas exhibiting 30-60 Lu. longipalpis and more than 60 Lu. longipalpis, the areas increased in both size and number from 2007-2009. Lu. longipalpis was more abundant in areas with a higher tree and bush cover (a macrohabitat characteristic) and in peridomiciles with accumulated unused material (a microhabitat characteristic). These results will help to prioritise and focus control efforts by defining which peridomiciles display a potentially high abundance of Lu. longipalpis. PMID:24271040
Control strategies for energy recovery from a flywheel using a vector controlled induction machine
R. Cardenas; R. Pena; G. Asher; J. Clare
This paper presents a novel control strategy for power smoothing in wind energy applications, especially those feeding a stand-alone load. The system is based on a vector controlled induction machine driving a flywheel and addresses the problem of regulating the DC-link system voltage against both input power surges\\/sags from a wind turbine or sudden changes in load demand. The control
Changing vessel routes could significantly reduce the cost of future offshore wind projects.
Samoteskul, Kateryna; Firestone, Jeremy; Corbett, James; Callahan, John
With the recent emphasis on offshore wind energy Coastal and Marine Spatial Planning (CMSP) has become one of the main frameworks used to plan and manage the increasingly complex web of ocean and coastal uses. As wind development becomes more prevalent, existing users of the ocean space, such as commercial shippers, will be compelled to share their historically open-access waters with these projects. Here, we demonstrate the utility of using cost-effectiveness analysis (CEA) to support siting decisions within a CMSP framework. In this study, we assume that large-scale offshore wind development will take place in the US Mid-Atlantic within the next decades. We then evaluate whether building projects nearshore or far from shore would be more cost-effective. Building projects nearshore is assumed to require rerouting of the commercial vessel traffic traveling between the US Mid-Atlantic ports by an average of 18.5 km per trip. We focus on less than 1500 transits by large deep-draft vessels. We estimate that over 29 years of the study, commercial shippers would incur an additional $0.2 billion (in 2012$) in direct and indirect costs. Building wind projects closer to shore where vessels used to transit would generate approximately $13.4 billion (in 2012$) in savings. Considering the large cost savings, modifying areas where vessels transit needs to be included in the portfolio of policies used to support the growth of the offshore wind industry in the US. PMID:24794388
Spatially-Explicit Simulation Modeling of Ecological Response to Climate Change: Methodological Considerations in Predicting Shifting Population Dynamics of Infectious Disease Vectors
Dhingra, Radhika; Jimenez, Violeta; Chang, Howard H.; Gambhir, Manoj; Fu, Joshua S.; Liu, Yang; Remais, Justin V.
Poikilothermic disease vectors can respond to altered climates through spatial changes in both population size and phenology. Quantitative descriptors to characterize, analyze and visualize these dynamic responses are lacking, particularly across large spatial domains. In order to demonstrate the value of a spatially explicit, dynamic modeling approach, we assessed spatial changes in the population dynamics of Ixodes scapularis, the Lyme disease vector, using a temperature-forced population model simulated across a grid of 4 � 4 km cells covering the eastern United States, using both modeled (Weather Research and Forecasting (WRF) 3.2.1) baseline/current (2001�2004) and projected (Representative Concentration Pathway (RCP) 4.5 and RCP 8.5; 2057�2059) climate data. Ten dynamic population features (DPFs) were derived from simulated populations and analyzed spatially to characterize the regional population response to current and future climate across the domain. Each DPF under the current climate was assessed for its ability to discriminate observed Lyme disease risk and known vector presence/absence, using data from the US Centers for Disease Control and Prevention. Peak vector population and month of peak vector population were the DPFs that performed best as predictors of current Lyme disease risk. When examined under baseline and projected climate scenarios, the spatial and temporal distributions of DPFs shift and the seasonal cycle of key questing life stages is compressed under some scenarios. Our results demonstrate the utility of spatial characterization, analysis and visualization of dynamic population responses�including altered phenology�of disease vectors to altered climate. PMID:24772388
Evaluation of QuikSCAT wind vector performance with respect to field measurements for the Bulgarian part of the Black Sea
Violeta Slabakova; Nataliya Andreeva; Petya Eftimova; Roumen Nedkov
Winds over the ocean play an important role in meteorology, oceanography and climatology. They affect air-sea variations in heat, humidity, gases and particles, regulating the crucial relation between the ocean and the atmosphere that establishes and supports the climate on regional and global scale. Therefore, the knowledge of wind fields over the oceans is essential for global weather forecast purposes.
The future of Antarctica's surface winds simulated by a high-resolution global climate model: 2. Drivers of 21st century changes
NASA Astrophysics Data System (ADS)
Bintanja, R.; Severijns, C.; Haarsma, R.; Hazeleger, W.
Antarctica's katabatic winds are among the strongest near-surface winds on Earth, and among the most consistent ones. As these winds are primarily due to the strong surface cooling, greenhouse warming of the surface may act to reduce the strength of these winds as well as their consistency. Here we use the atmospheric component of the global climate model EC-Earth in prescribed sea surface temperature (SST) simulations of the present day (2002-2006) and future (2094-2098) climates, using two model resolutions: (1) T159L62 (~100 km, 62 vertical levels), and (2) T799L91 (~20 km, 91 vertical levels) to investigate changes in Antarctica's surface winds and the reasons thereof. Circumpolar westerlies over the Southern Ocean strengthen and shift poleward because of the deepening of the circumpolar trough and the associated increase in Southern Annular Mode (SAM), especially in high resolution, causing weaker coastal easterlies. Generally, surface wind speeds over the Antarctica mainland exhibit a small decrease. According to the simulations, the temperature deficit (or inversion strength) and associated katabatic forcing exhibit only minor changes over the continent. Changes in the surface winds over Antarctica's slopes can thus be attributed mainly to changes in the synoptic forcing (large-scale pressure gradient). Hence, with modeled 21st century changes in the katabatic forcing being small, changes in zonal and meridional surface winds in and around Antarctica are largely decoupled from those over the Southern Ocean and are governed by changes in synoptic forcing and large-scale pressure gradients. As a result, these changes are largely independent on model resolution.
Centennial changes in the solar wind speed and in the open solar flux
A. P. Rouillard; M. Lockwood; I. Finch
We use combinations of geomagnetic indices, based on both variation range and hourly means, to derive the solar wind flow speed, the interplanetary magnetic field strength at 1 AU and the total open solar flux between 1895 and the present. We analyze the effects of the regression procedure and geomagnetic indices used by adopting four analysis methods. These give a
Southern Hemisphere Westerly Wind Changes during the Last Glacial Maximum: Model-Data Comparison
De Boer, Agatha M.
Glacial Maximum (LGM). Using LGM boundary conditions,9 the maximum in SH westerlies is strengthened by +1 over equatorward extended LGM sea-ice can lead to a small appar-12 ent equatorward shift in the wind against the newly synthesised17 database of moisture observations for the LGM. Although the moisture data
VOL. 66, NO. 4 (DECEMBER 2013) P. 448458 Changing Daily Wind Speeds on Alaska's North Slope
to hunt bowhead whale (Balaena mysticetus) during spring and caribou (Rangifer tarandus) during summer. We printemps, et du caribou (Rangifer tarandus) � l'�t�. Nous avons int�gr� les observations des chasseurs au with wind conditions suitable for safely hunting bowhead whales and caribou. The statistical analysis
More Variable and Stronger Winds during the Last Glacial
NASA Astrophysics Data System (ADS)
Dietrich, Stephan; Werner, Martin; Lohmann, Gerrit
Changes of wind systems and thus of atmospheric circulation patterns are an essential feature of fast climate changes that explain hemispheric wide teleconnections. Here, we present the synoptic interpretation of prevailing paleo wind systems for Central Europe during glacial times and compare the results with a proxy record of changes from easterly to westerly wind directions from maar lake sediments (Germany). This record indicates a high amount of east wind and a high variability on a millennial time scale of wind direction changes for the last glacial period. The basic observations, made on the proxy record, are also shown in the 10 m-wind vectors in ECHAM3 and ECHAM4 model experiments under glacial conditions with different prescribed sea surface temperature patterns. However, all glacial experiments show a lower frequency of east wind in comparison to the present-day control runs. But all glacial runs show a high variability of wind direction changes and stronger winds in comparison to the present-day control runs. Furthermore, the analysis of long-persisting east wind conditions (so-called LEWIC events) in the AGCM data shows a stronger seasonality during glacial conditions: all different experiments are characterized by an increase of the relative importance during spring and summer. Synoptic analysis of the air flows with prevailing east wind over Central Europe are given for the spring which is the most important season for dust emission. Under present-day conditions easterly wind directions are mainly forced by a strong high over the Baltic Sea realm. The different glacial experiments show in good agreement a shift from a long-lasting high from the Baltic Sea towards NW, directly above the Scandinavian Ice Sheet, together with the contemporary occurrence of enhanced westerly circulation at the North Atlantic.
Vector Introduction Vector components and example machines
California at Berkeley, University of
vector 1 Vector Introduction Lecture 10 2/21/96 vector 2 Outline Motivation Vector components and example machines Vector instructions & vector program Vector Execution Vector Load/Store Units Vector Length, Stride, Strip Mining Vector Optimizations: Chaining, Gather/Scatter, Conditional Vector Metrics
Migrating swans profit from favourable changes in wind conditions at low altitude
Marcel Klaassen; Jan H. Beekman; Jari Kontiokorpi; Roef J. W. Mulder; Bart A. Nolet
Because energy reserves limit flight range, wind assistance may be of crucial importance for migratory birds. We tracked eight Bewick�s swans Cygnus columbianus bewickii, using 95-g satellite transmitters with altimeters and activity sensors, during their spring migration from Denmark to northern Russia in 1996. During the 82 occasions where a swan�s location was recorded in flight, average flight altitude was
Response of the Earth's Magnetosphere to Changes in the Solar Wind
NASA Technical Reports Server (NTRS)
McPherron, Robert L.; Weygand, James M.; Hsu, Tung-Shin
The solar wind couples to the magnetosphere via dynamic pressure and electric field. Pressure establishes the size and shape of the system, while the electric field transfers energy, mass, and momentum to the magnetosphere. When the interplanetary magnetic field (IMF) is antiparallel to the dayside magnetic field, magnetic reconnection connects the IMF to the dipole field. Solar wind transport of the newly opened field lines to the nightside creates an internal convection system. These open field lines must ultimately be closed by reconnection on the nightside. For many decades, it was thought that a magnetospheric substorm was the process for accomplishing this and that all magnetic activity was a consequence of substorms. It is now recognized that there are a variety of modes of response of the magnetosphere to the solar wind. In this paper, we briefly describe these modes and the conditions under which they occur. They include substorms, pseudo-breakups, poleward boundary intensifications (PBI), steady magnetospheric convection (SMC), sawtooth injection events, magnetic storms, high-intensity long-duration continuous AE activities (HILDCAAs), and storm-time activations. There are numerous explanations for these different phenomena, some of which do not involve magnetic reconnection. However, we speculate that it is possible to interpret each mode in terms of differences in the way magnetic reconnection occurs on the nightside.
Vector continued fractions using a generalized inverse
NASA Astrophysics Data System (ADS)
Haydock, Roger; Nex, C. M. M.; Wexler, Geoffrey
A real vector space combined with an inverse (involution) for vectors is sufficient to define a vector continued fraction whose parameters consist of vector shifts and changes of scale. The choice of sign for different components of the vector inverse permits construction of vector analogues of the Jacobi continued fraction. These vector Jacobi fractions are related to vector and scalar-valued polynomial functions of the vectors, which satisfy recurrence relations similar to those of orthogonal polynomials. The vector Jacobi fraction has strong convergence properties which are demonstrated analytically, and illustrated numerically.
Structural changes of the follicular cells during developmental stages of the malaria vector mosquitoes Anopheles pharoensis (Diptera: Culicidae) in Egypt.
Yamany, Abeer S; Adham, Fatma K; Mehlhorn, Heinz
The structure modulation of follicular cells and the ovarian changes during fourth larval instar and pupal stage of the malaria vector mosquitoes Anopheles pharoensis Theobald were investigated using the light and electron microscopy. The generative organs consist of a pair of polytrophic ovaries (OV), which are oblong, spindle-shaped bodies, lying dorsolaterally and occupying the region from the mid-fifth to the mid-sixth abdominal segment in the fourth larval instar, while in the pupal stage, each ovary (OV) is situated in the haemocoel of the sixth abdominal segment. It is an oblong body slightly larger in diameter; the lumen of the calyx becomes wider and central, and the pedicel (P) consists of one row of compact discoidal cells; meanwhile, in the fourth larval instar, the pedicel is without a lumen and consists of two rows of discoidal cells which are arranged as a short column between the follicle and calyx. The mean volume of the follicle in the fourth larval instar is 9.078?�?3.0178�?m(3), meanwhile in the pupal stage being 12.051?�?2.427�?m(3). The germarium (G) decreases in size in the pupal stage and contains a group of cells from which the oogonia differentiate, follicular cells which are similar to trophocytes, undifferentiated into one oocyte (O), which will develop into an egg and it is statistically the smallest one measured (0.058?�?0.0041�?m(3), 0.303?�?0.0086�?m(3)) in fourth larval instar and pupal stage, respectively as compared to the others within the follicle which will be accompanied as nurse cells (NC). The follicle is enclosed by a mononuclear flattened cells (follicular membrane), which have distinct boundaries. The vitellarium is differentiated into primary (F1) and secondary follicles (F2) in the pupal stage. The Golgi apparatus (GA) appears as discrete bits which are restricted to the perinuclear zone. The mitochondria (M) in the fourth larval instar are in the form of granules and short rods. They are perinuclearly distributed, forming a ring that surrounds the comparatively large nucleus. In the pupal stage, a similar condition to that described for the larva is observed, but with an increase in size and numbers, due to breaking up of rods into granules. PMID:25241910
Wind turbine wake aerodynamics
L. J. Vermeer; J. N. S�rensen; A. Crespo
The aerodynamics of horizontal axis wind turbine wakes is studied. The contents is directed towards the physics of power extraction by wind turbines and reviews both the near and the far wake region. For the near wake, the survey is restricted to uniform, steady and parallel flow conditions, thereby excluding wind shear, wind speed and rotor setting changes and yawed
Virus-mediated chemical changes in rice plants impact the relationship between non-vector planthopper Nilaparvata lugens St�l and its egg parasitoid Anagrus nilaparvatae Pang et Wang.
He, Xiaochan; Xu, Hongxing; Gao, Guanchun; Zhou, Xiaojun; Zheng, Xusong; Sun, Yujian; Yang, Yajun; Tian, Junce; Lu, Zhongxian
In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae. PMID:25141278
Climate change effects on mitigation measures: The case of extreme wind events and Philippines� biofuel plan
Per M. Stromberg; Miguel Esteban; Alexandros Gasparatos
Biofuel production has increased dramatically over the past decade, among other to mitigate climate change. However, climate change vulnerability may currently not be sufficiently accounted for in national biofuel strategies, hence neglecting a possible link between mitigation and adaptation to climate change. To the best of our knowledge this potential link has received very little attention in the literature. One
Impact of land use change on wind erosion and dust emission: scenarios from the central US
Technology Transfer Automated Retrieval System (TEKTRAN)
There will be significant changes in land cover and land use throughout the central United States in the coming years, particularly as a result of climate change, changes in US rangeland/farm policy, and increasing exploitation of land-intensive sustainable energy sources. The purpose of this study ...
NASA Astrophysics Data System (ADS)
Keskinen, M. J.; Beget, J. E.
Ice wedge casts and thermokarst deposits near the base of 80-m-high loess cliffs at Gold Hill record a cycle of transient climate cooling and permafrost formation followed by an interval of climate warming and permafrost degradation about two million years ago (Beget et al., 2008). Ice wedge casts and thermokarst features occur below the PA tephra (ca. 2.02 myr) but formed after the Reunion paleomagnetic excursion (ca. 2.14 myr), suggesting the Alaskan cold interval was correlative with marine isotope stage 77, a time of significant global glaciation and cooling. The subsequent period of ice wedge thawing records warmer conditions, probably during marine isotope stage 76. Magnetic susceptibility profiling of the 2 MA Alaskan loess reveals glacial-interglacial cycles similar to those seen in late Pleistocene loess. However, new geochemical data from the 2 MA loess shows that it was significantly more calcareous then late Pleistocene loess and contains numerous calcareous concretions, some weighing as much as several kg. For most of the past two million years the loess geochemistry indicates winds came dominantly from the south and southwest carrying non-calcarous silts derived from glaciation of the Alaska Range, with only a minor eolian contribution from the calcareous-rich silts of the Yukon River. The calcareous loess deposits that formed 2.1 MA record eolian silt transport from the Yukon River and the calcareous Brooks Range to the north. The loess record shows that an interval characterized by a major shift in the atmospheric circulation regime from one dominated by southerly winds from the northern Pacific Ocean and Gulf of Alaska to one dominated by northerly winds from the Chuckchi Sea and western Arctic Ocean areas occurred ca. 2.1 MA. At least one additional interval of calcareous loess deposition also occurs in mid-Pleistocene time, and records another large but transient change in high latitude atmospheric circulation at ca. 0.4-0.5 MA.
Decades-long changes of the interstellar wind through our solar system.
Frisch, P C; Bzowski, M; Livadiotis, G; McComas, D J; Moebius, E; Mueller, H-R; Pryor, W R; Schwadron, N A; Sok�?, J M; Vallerga, J V; Ajello, J M
The journey of the Sun through the dynamically active local interstellar medium creates an evolving heliosphere environment. This motion drives a wind of interstellar material through the heliosphere that has been measured with Earth-orbiting and interplanetary spacecraft for 40 years. Recent results obtained by NASA's Interstellar Boundary Explorer mission during 2009-2010 suggest that neutral interstellar atoms flow into the solar system from a different direction than found previously. These prior measurements represent data collected from Ulysses and other spacecraft during 1992-2002 and a variety of older measurements acquired during 1972-1978. Consideration of all data types and their published results and uncertainties, over the three epochs of observations, indicates that the trend for the interstellar flow ecliptic longitude to increase linearly with time is statistically significant. PMID:24009386
Rapid changes in mixed layer stratification driven by submesoscale instabilities and winds
Ferrari, Raffaele
Click Here for Full Article Rapid changes in mixed layer stratification driven by submesoscale: Mahadevan, A., A. Tandon, and R. Ferrari (2010), Rapid changes in mixed layer stratification driven and reduce stratification. Con- versely, precipitation and heating at the surface cause restratification
Medical Education in the Anatomical Sciences: The Winds of Change Continue to Blow
ERIC Educational Resources Information Center
Drake, Richard L.; McBride, Jennifer M.; Lachman, Nirusha; Pawlina, Wojciech
At most institutions, education in the anatomical sciences has undergone several changes over the last decade. To identify the changes that have occurred in gross anatomy, microscopic anatomy, neuroscience/neuroanatomy, and embryology courses, directors of these courses were asked to respond to a survey with questions pertaining to total course�
Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research
NASA Technical Reports Server (NTRS)
Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,
Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.
Short-Term Wind Power Forecasts using Doppler Lidar
NASA Astrophysics Data System (ADS)
Magerman, Beth
With a ground-based Doppler lidar on the upwind side of a wind farm in the Tehachapi Pass of California, radial wind velocity measurements were collected for repeating sector sweeps, scanning up to 10 kilometers away. This region consisted of complex terrain, with the scans made between mountains. The dataset was utilized for techniques being studied for short-term forecasting of wind power by correlating changes in energy content and of turbulence intensity by tracking spatial variance, in the wind ahead of a wind farm. A ramp event was also captured and its propagation was tracked. Orthogonal horizontal wind vectors were retrieved from the radial velocity using a sector Velocity Azimuth Display method. Streamlines were plotted to determine the potential sites for a correlation of upstream wind speed with wind speed at downstream locations near the wind farm. A "virtual wind turbine" was "placed" in locations along the streamline by using the time-series velocity data at the location as the input to a modeled wind turbine, to determine the extractable energy content at that location. The relationship between this time-dependent energy content upstream and near the wind farm was studied. By correlating the energy content with each upstream location based on a time shift estimated according to advection at the mean wind speed, several fits were evaluated. A prediction of the downstream energy content was produced by shifting the power output in time and applying the best-fit function. This method made predictions of the power near the wind farm several minutes in advance. Predictions were also made up to an hour in advance for a large ramp event. The Magnitude Absolute Error and Standard Deviation are presented for the predictions based on each selected upstream location.
Short Time Scale Changes in Underwater Irradiance in a Wind-exposed Lagoon (Vaccar�s Lagoon, France): Efficiency of Infrequent Field Measurements of Water Turbidity or Weather Data to Predict Irradiance in the Water Column
Damien Banas; Patrick Grillas; Isabelle Auby; Fran�ois Lescuyer; Eric Coulet; Jean-Claude Moreteau; Bertrand Millet
High frequency water sampling in the wind-exposed Vaccar�s lagoon revealed frequent and rapid changes in suspended solid (SS) concentrations in the water column. SS concentrations, sometimes higher than 800 mg�l?1, were significantly correlated with antecedent wind conditions. Mean wind velocity during the 5�33�h before water sampling or maximal wind velocity during the previous 8.5�22�h were good predictors of SS concentrations
The National assessment of shoreline shange�A GIS compilation of vector shorelines and associated shoreline change data for the Pacific Northwest coast
Kratzmann, Meredith; Himmelstoss, Emily A.; Ruggiero, Peter; Thieler, E. Robert; Reid, David
Sandy ocean beaches are a popular recreational destination and are often surrounded by communities that consist of valuable real estate. Development along sandy coastal areas is increasing despite the fact that coastal infrastructure may be repeatedly subjected to flooding and erosion. As a result, the demand for accurate information regarding past and present shoreline changes is increasing. Investigators with the U.S. Geological Survey's National Assessment of Shoreline Change Project have compiled a comprehensive database of digital vector shorelines and rates of shoreline change for the Pacific Northwest coast including the states of Washington and Oregon. No widely accepted standard for analyzing shoreline change currently exists. Current measurement and methods for calculating rates of change vary from study to study, precluding the combination of study results into statewide or regional assessments. The impetus behind the national assessment was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the measurements in an internally consistent manner. A detailed report on shoreline change for the Pacific Northwest coast that contains a discussion of the data presented here is available and cited in the Geospatial Data section of this report.
Changes in solar wind-magnetosphere coupling with solar cycle, season, and time relative to stream interfaces
NASA Astrophysics Data System (ADS)
McPherron, Robert L.; Baker, Daniel N.; Pulkkinen, T. I.; Hsu, T.-S.; Kissinger, J.; Chu, X.
Geomagnetic activity depends on a variety of factors including solar zenith angle, solar UV, strength of the interplanetary magnetic field, speed and density of the solar wind, orientation of the Earth�s dipole, distance of the Earth from Sun, occurrence of CMEs and CIRs, and possibly other parameters. We have investigated some of these using state-dependant linear prediction filters. For a given state a prediction filter transforms a coupling function such as rectified solar wind electric field (VBs) to an output like the auroral electrojet index (AL). The area of this filter calculated from the sum of the filter coefficients measures the strength of the coupling. When the input and output are steady for a time longer than the duration of the filter the ratio of output to input is equal to this area. We find coupling strength defined in this way for Es=VBs to AL (and AU) is weakest at solar maximum and strongest at solar minimum. AL coupling displays a semiannual variation being weakest at the solstices and strongest at the equinoxes. AU coupling has only an annual variation being strongest at summer solstice. AL and AU coupling also vary with time relative to a stream interface. Es coupling is weaker after the interface, but ULF coupling is stronger. Total prediction efficiency remains about constant at the interface. The change in coupling strength with the solar cycle can be explained as an effect of more frequent saturation of the polar cap potential causing a smaller ratio of AL to Es. Stronger AL coupling at the equinoxes possibly indicates some process that makes magnetic reconnection less efficient when the dipole axis is tilted along the Earth-Sun line. Strong AU coupling at summer solstice is likely due to high conductivity in northern summer. Coupling changes at a stream interface are correlated with the presence of strong wave activity in ground and satellite measurements and may be an artifact of the method by which solar wind data are propagated.
Dave Glidden is a Field Specialist in Wind and Mountain Climatology, and has conducted wind studies for the National Park Service in Rocky Mountain National Park in Colorado. More recently, he has pursued field work on the variability of mountain winds and gust factors in Denali National Park in Alaska. A strong advocate of women in the sciences, he has
Rice stripe virus affects the viability of its vector offspring by changing developmental gene expression in embryos.
Li, Shuo; Wang, Shijuan; Wang, Xi; Li, Xiaoli; Zi, Jinyan; Ge, Shangshu; Cheng, Zhaobang; Zhou, Tong; Ji, Yinghua; Deng, Jinhua; Wong, Sek-Man; Zhou, Yijun
Plant viruses may affect the viability and development process of their herbivore vectors. Small brown planthopper (SBPH) is main vector of Rice stripe virus (RSV), which causes serious rice stripe disease. Here, we reported the effects of RSV on SBPH offspring by crossing experiments between viruliferous and non-viruliferous strains. The life parameters of offspring from different cross combinations were compared. The hatchability of F1 progeny from viruliferous parents decreased significantly, and viruliferous rate was completely controlled by viruliferous maternal parent. To better elucidate the underlying biological mechanisms, the morphology of eggs, viral propagation and distribution in the eggs and expression profile of embryonic development genes were investigated. The results indicated that RSV replicated and accumulated in SBPH eggs resulting in developmental stunt or delay of partial eggs; in addition, RSV was only able to infect ovum but not sperm. According to the expression profile, expression of 13 developmental genes was regulated in the eggs from viruliferous parents, in which two important regulatory genes (Ls-Dorsal and Ls-CPO) were most significantly down-regulated. In general, RSV exerts an adverse effect on SBPH, which is unfavourable for the expansion of viruliferous populations. The viewpoint is also supported by systematic monitoring of SBPH viruliferous rate. PMID:25601039
Rice stripe virus affects the viability of its vector offspring by changing developmental gene expression in embryos
Li, Shuo; Wang, Shijuan; Wang, Xi; Li, Xiaoli; Zi, Jinyan; Ge, Shangshu; Cheng, Zhaobang; Zhou, Tong; Ji, Yinghua; Deng, Jinhua; Wong, Sek-Man; Zhou, Yijun
Plant viruses may affect the viability and development process of their herbivore vectors. Small brown planthopper (SBPH) is main vector of Rice stripe virus (RSV), which causes serious rice stripe disease. Here, we reported the effects of RSV on SBPH offspring by crossing experiments between viruliferous and non-viruliferous strains. The life parameters of offspring from different cross combinations were compared. The hatchability of F1 progeny from viruliferous parents decreased significantly, and viruliferous rate was completely controlled by viruliferous maternal parent. To better elucidate the underlying biological mechanisms, the morphology of eggs, viral propagation and distribution in the eggs and expression profile of embryonic development genes were investigated. The results indicated that RSV replicated and accumulated in SBPH eggs resulting in developmental stunt or delay of partial eggs; in addition, RSV was only able to infect ovum but not sperm. According to the expression profile, expression of 13 developmental genes was regulated in the eggs from viruliferous parents, in which two important regulatory genes (Ls-Dorsal and Ls-CPO) were most significantly down-regulated. In general, RSV exerts an adverse effect on SBPH, which is unfavourable for the expansion of viruliferous populations. The viewpoint is also supported by systematic monitoring of SBPH viruliferous rate. PMID:25601039
Electrical Wind Force-Driven and Dislocation-Templated Amorphization in Phase-Change Nanowires
NASA Astrophysics Data System (ADS)
Nam, Sung-Wook; Chung, Hee-Suk; Lo, Yu Chieh; Qi, Liang; Li, Ju; Lu, Ye; Johnson, A. T. Charlie; Jung, Yeonwoong; Nukala, Pavan; Agarwal, Ritesh
Phase-change materials undergo rapid and reversible crystalline-to-amorphous structural transformation and are being used for nonvolatile memory devices. However, the transformation mechanism remains poorly understood. We have studied the effect of electrical pulses on the crystalline-to-amorphous phase change in a single-crystalline Ge2Sb2Te5 (GST) nanowire memory device by in situ transmission electron microscopy. We show that electrical pulses produce dislocations in crystalline GST, which become mobile and glide in the direction of hole-carrier motion. The continuous increase in the density of dislocations moving unidirectionally in the material leads to dislocation jamming, which eventually induces the crystalline-to-amorphous phase change with a sharp interface spanning the entire nanowire cross section. The dislocation-templated amorphization explains the large on/off resistance ratio of the device.
Winds of Change in the English Language--Air of Peril for Native Speakers?
ERIC Educational Resources Information Center
Paradowski, Michal B.
English today is one of the most hybrid and rapidly changing languages in the world. New users of the language are not just passively absorbing, but actively shaping it, breeding a variety of regional Englishes, as well as pidgins and English-lexified creoles. Also, as in an increasing number of countries English is becoming an element of core�
Winds of Change: A Colloquium in Music Education (College Park, Maryland, April 3, 1993). State of the Arts Series No. 1.
ERIC Educational Resources Information Center
Fowler, Charles; Elliott, David J.
The volume contains papers presented at "Winds of Change: A Colloquium in Music Education," and examines the current need for reform in music education. Assessments of music's failure to achieve central curricular status, and outline scenarios for reform and improved status for music education are presented. The reform plans emphasize the value of�
The impact of Climate Change on the Iberian Low-Level Wind Jet: EURO-CORDEX regional climate simulation
NASA Astrophysics Data System (ADS)
Cardoso, Rita M.; Soares, Pedro M. M.; Lima, Daniela; Semedo, �lvaro
A sharp temperature contrast, observed mostly in summer, between high temperatures over land and lower temperatures over the ocean and the typical summer synoptic scale configuration (high pressure system over the ocean and thermal low inland) are responsible for the development of a coastal low-level jet (CLLJ). The low level horizontal pressure gradient induces, through geostrophic adjustment, a strong alongshore flow, which is also influenced by local orography and the high pressure subsidence over the maritime boundary layer. In this study, the EURO-CORDEX hindcast forced by ERA-Interim (1989-2009), the historic reference (1960-2006) and the future (2006-2100; RCP8.5) simulations, forced by EC-Earth global model, are used to determine the climate change signal on the CLLJ off the Iberian Peninsula's western coast. Although the boundary conditions of the hindcast and historic reference simulations have different resolutions, both have similar distributions and features of CLLJ. In the summer, a clear rise in the occurrence of CLLJ is expected throughout the 21st century, with the highest increase off the northwest coast of Iberia (~14%). The CLLJ prevailing height is confined between 300 and 400m and the most frequent maximum wind speed is 15ms-1 both in present and future climate, nevertheless a shift to higher values is expected. The predominant wind direction at jet height is north-northeast in all simulations. The temporal evolution of CLLJ occurrence during the 21st century shows that there is no significant trend in spring and autumn, although some decadal variability is observed.
Three Dimensional Dynamic Model Based Wind Field Reconstruction from Lidar Data
NASA Astrophysics Data System (ADS)
Raach, Steffen; Schlipf, David; Haizmann, Florian; Cheng, Po Wen
Using the inflowing horizontal and vertical wind shears for individual pitch controller is a promising method if blade bending measurements are not available. Due to the limited information provided by a lidar system the reconstruction of shears in real-time is a challenging task especially for the horizontal shear in the presence of changing wind direction. The internal model principle has shown to be a promising approach to estimate the shears and directions in 10 minutes averages with real measurement data. The static model based wind vector field reconstruction is extended in this work taking into account a dynamic reconstruction model based on Taylor's Frozen Turbulence Hypothesis. The presented method provides time series over several seconds of the wind speed, shears and direction, which can be directly used in advanced optimal preview control. Therefore, this work is an important step towards the application of preview individual blade pitch control under realistic wind conditions. The method is tested using a turbulent wind field and a detailed lidar simulator. For the simulation, the turbulent wind field structure is flowing towards the lidar system and is continuously misaligned with respect to the horizontal axis of the wind turbine. Taylor's Frozen Turbulence Hypothesis is taken into account to model the wind evolution. For the reconstruction, the structure is discretized into several stages where each stage is reduced to an effective wind speed, superposed with a linear horizontal and vertical wind shear. Previous lidar measurements are shifted using again Taylor's Hypothesis. The wind field reconstruction problem is then formulated as a nonlinear optimization problem, which minimizes the residual between the assumed wind model and the lidar measurements to obtain the misalignment angle and the effective wind speed and the wind shears for each stage. This method shows good results in reconstructing the wind characteristics of a three dimensional turbulent wind field in real-time, scanned by a lidar system with an optimized trajectory.
Cheney, Jr., Marvin C. (Glastonbury, CT)
A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.
How do cosmic rays change their energy in the solar wind?
NASA Technical Reports Server (NTRS)
Jones, F. C.
The diffusion-convection (modulation) equation is derived directly from the Boltzmann equation on the basis of a minimum number of assumptions concerning the scattering process, among which are: (1) that the scattered particles undergo no energy change, and (2) that isotropy is an equilibrium state. It is noted that, in the event that the background plasma contains a magnetic field and the flow speeds of the plasma and scattering centers are different, additional terms arise that will modify the equations. If, moreover, the scatterers have individual motions relative to their average flow, the second-order Fermi acceleration term will appear.
Stochastic Dynamics of Sea Surface Winds Adam Hugh Monahan
Monahan, Adam Hugh
Stochastic Dynamics of Sea Surface Winds Adam Hugh Monahan School of Earth and Ocean Sciences The probability distribution of sea surface winds (both vector winds and wind speed) is considered. The observed moment fields, estimated from SeaWinds scatterometer data, are shown to be characterised by non
Assessing climate change impacts on the near-term stability of the wind energy resource over the United States.
Pryor, S C; Barthelmie, R J
The energy sector comprises approximately two-thirds of global total greenhouse gas emissions. For this and other reasons, renewable energy resources including wind power are being increasingly harnessed to provide electricity generation potential with negligible emissions of carbon dioxide. The wind energy resource is naturally a function of the climate system because the "fuel" is the incident wind speed and thus is determined by the atmospheric circulation. Some recent articles have reported historical declines in measured near-surface wind speeds, leading some to question the continued viability of the wind energy industry. Here we briefly articulate the challenges inherent in accurately quantifying and attributing historical tendencies and making robust projections of likely future wind resources. We then analyze simulations from the current generation of regional climate models and show, at least for the next 50 years, the wind resource in the regions of greatest wind energy penetration will not move beyond the historical envelope of variability. Thus this work suggests that the wind energy industry can, and will, continue to make a contribution to electricity provision in these regions for at least the next several decades. PMID:21536905
Robert M. Gray
A vector quantizer is a system for mapping a sequence of continuous or discrete vectors into a digital sequence suitable for communication over or storage in a digital channel. The goal of such a system is data compression: to reduce the bit rate so as to minimize communication channel capacity or digital storage memory requirements while maintaining the necessary fidelity
Wind farm and solar park effects on plant�soil carbon cycling: uncertain impacts of changes in ground-level microclimate
Armstrong, Alona; Waldron, Susan; Whitaker, Jeanette; Ostle, Nicholas J
Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant�soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant�soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research. PMID:24132939
Winds of change: growing demands for transparency in the relationship between doctors and the pharmaceutical industry.
Mitchell, Philip B
The relationship between medicine and the pharmaceutical industry in the United States is undergoing rapid and momentous change; US Senator Grassley has alleged inadequate disclosure of earnings from industry and lack of acknowledgement of conflicts of interest by leading academics. This article is based on the premise that it is not the relationship per se that is the problem, but rather how that relationship is enacted. The influential 2008 report of the Association of American Medical Colleges (AAMC) has provided detailed recommendations on appropriate interactions between academic physicians and industry (eg, proscribing receipt of gifts including travel support, and proscribing speaking at industry-sponsored educational programs). Contrary to expectations, there has been widespread acceptance of such guidelines. In Australia, details of all industry-sponsored educational events are now listed on the Medicines Australia website. Australian doctors have no alternative but to drastically improve the transparency of their interactions with industry, both in terms of the remuneration received and disclosure of potential conflicts of interest. Australian universities should seriously consider developing recommendations similar to those of the AAMC. PMID:19740050
Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- by 15-foot low speed wind tunnel
NASA Technical Reports Server (NTRS)
Johns, Albert L.; Neiner, George; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.
A 9.2 percent scale STOVL hot gas ingestion model was tested in the NASA Lewis 9 x 15-foot Low-Speed Wind Tunnel. Flow visualization from the Phase 1 test program, which evaluated the hot ingestion phenomena and control techniques, is covered. The Phase 2 test program evaluated the hot gas ingestion phenomena at higher temperatures and used a laser sheet to investigate the flow field. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/life improvement devices (LIDs) which reduced the hot gas ingestion. The test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. Results are presented over a range of nozzle pressure ratios at a 10 kn headwind velocity. The Phase 2 program was conducted at exhaust nozzle temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. The results reported are for nozzle exhaust temperatures up to 1160 R and contain the compressor face pressure and temperature distortions, the total pressure recovery, the inlet temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane contours, the model airframe heating, and the location of the ground flow separation.
Anthropogenic Landscape Change and Vectors in New Zealand: Effects of Shade and Nutrient Levels on Mosquito Productivity
Paul T. Leisnham; Philip J. Lester; David P. Slaney; Philip Weinstein
Anthropogenic environmental changes, such as deforestation, agriculture, and introduced exotic species, have often coincided with an increase in mortality and morbidity from mosquito-borne diseases worldwide. Deforestation and agricultural development are likely to regulate immature mosquito populations through the addition of nutrients from livestock waste, decreased shade resulting in increased insolation (solar radiation), and the proliferation of artificial container habitats. We
Roles of surface wind, NDVI and snow cover in the recent changes in Asian dust storm occurrence frequency
NASA Astrophysics Data System (ADS)
Lee, Jong-Jae; Kim, Cheol-Hee
This paper describes the recent variations in dust outbreak during the period from 1996 to 2007 over the Asian dust source regions. The Asian dust source regions were divided into four sub-regions; S1, Taklamakan; S2, Gobi; S3, Inner Mongolia-Manchuria; and S4, Loess, and the WMO SYNOP observation and satellite data were employed to analyze the features of recently changed dust outbreak frequencies (DOFs). There was no particular variation in region S1, but the recent spatiotemporal variations in DOFs over S2-S4 were well characterized by a severe and widespread increase in 2001-2002, and significant decreasing in 2003-2004 over the most source regions, with a steadily increasing trend again during 2005-2007. Seasonal features showed that the highest DOFs occurred in March-April before 2002, but was delayed by a month toward April-May during the next five years because of the shift in the month of highest strong wind-speed frequencies (SWFs). A secondary peak of DOF was also found, occurring in October-November since the year 2000. Over all the source regions, the primary controlling factor for explaining the spatiotemporal DOF patterns was the SWF, with a pattern correlation coefficient (PCC) of 0.66-0.76. Other secondary controlling factors varied from region to region. For example, the DOFs observed in region S2-S3 showed relatively greater sensitivity to the snow-cover fraction, and region S4 showed a better correlation with the normalized difference vegetation index (NDVI) than the other regions. Other recent significant changes in DOFs over the Asian dust source regions and their causes are also discussed in this study.
Phase alignment for coherent and vector processing
NASA Astrophysics Data System (ADS)
Wagstaff, Ronald A.
Acoustic phase angle is seldom used to achieve signal-to-noise ratio (SNR) gain for single sensor and beam spectral output. One reason is that phase angles generally progress at a nonuniform rate, with unpredictable changes in the direction of rotation. This causes fluctuations in the phase angles with corresponding reductions in gain, often including severe attenuation and cancellation of signals. By adopting a particular analytically convenient definition for phase fluctuations, the fluctuations, thus defined, constitute a set of aligned-phase angles. The aligned-phase angles can be used instead of phase angles to form phase-aligned coherent and vector averages. Doing so achieves SNR gains that equal or exceed the theoretical value of 10 log(N) for perfectly coherent vector averaging (N is the number of elements averaged). This is accomplished without the signal attenuation and cancellation common to coherent and vector averaging. Furthermore, the aligned-phase angles can also be used to automatically detect signals, based on both phase-aligned coherence and appropriate averaging of the aligned-phase angles. Results are included for wind noise in outdoor measurements. [Work supported by U.S. Army Space and Missile Defense Command.
The Effects of Abrupt Wind Shears in the Solar Wind on the Earth's Magnetosphere
NASA Astrophysics Data System (ADS)
Borovsky, J.; Boudouridis, A.; Birn, J.; Denton, M.
The solar wind is filled sudden velocity shears. The shears take the form of vorticity layers co-located with current sheets. The velocity vector makes its change in a few seconds. For shear layers with vector velocity changes greater than 50 km/s, an average of 12 shear layers pass the Earth per day. Global magnetospheric MHD simulations with four different simulation codes have been performed at the Community Coordinated Modeling Center (CCMC) to examine the reaction of the Earth to the solar-wind velocity shears. All 4 simulation codes predict comet-like disconnections of the magnetotail, the magnetosheath, and the bow shock on the flanks as a shear layer passes the Earth. The simulation codes also predict sudden changes in the cross-polar-cap potential and ionospheric Joule dissipation as the shear layers pass the Earth. A data-analysis research effort is underway to look for signatures of the Earth's reaction to abrupt wind shear events; preliminary results of that effort will be discussed.
Estimation of sea surface winds using reflected GPS signals
NASA Astrophysics Data System (ADS)
Armatys, Michael James
This dissertation presents algorithms and results for GPS-based remote sensing of ocean surface wind speed and direction. Results are given from aircraft experiments and simulations are shown for a spaceborne platform. The algorithm matches predictions of reflected signal power distribution in delay and Doppler with waveforms measured by a specialized receiver. The wind retrieval algorithm for airborne receivers comprises two parts: a least-squares estimator of the surface slope variances and a solution for wind speed and direction. The state vector consists of the slope variances and covariance in the East, North, Up reference frame and a fixed path delay offset. The state estimate is that state which minimizes the sum-of-squares residual between the measured and predicted waveforms. Model waveforms for aircraft altitudes are generated using an electromagnetic model developed by V. Zavorotny and A. Voronovich. Airborne experiments were conducted using a Delay Mapping Receiver (DMR) developed at the NASA Langley Research Center (LaRC). In situ measurements used as sources of truth include buoys and QuikSCAT scatterometer measurements. GPS-based estimates agree with in situ measurements to within 1 m/s and 5 degrees for data sets containing well-defined wind fields, long fetch, and high GPS satellite elevation angles. The results of the visibility analysis are used in a sensitivity and wind retrieval resolution analysis. The sensitivity analysis identifies the regions of the glistening zone that have the greatest change in power for changes in wind speed and direction. The analysis shows that the waveform peaks and trailing edges should be used to estimate wind speed and regions of the waveform trailing edge should be used to estimate wind direction. The resolution analysis determines the accuracy with which wind vectors can be estimated over the glistening zone for varying wind conditions. Results show that wind can be retrieved to within 1 m/s and 20 deg over large portions of the glistening zone with as few as 3000 0.3 ms observations at low wind speeds. The resolution degrades for higher wind speeds, requiring far more observations to achieve comparable retrieval accuracy. (Abstract shortened by UMI.)
Changes in water and wind resources across the central and northeastern U.S. 2060-2010 in 24 km WRF downscale climate simulations
NASA Astrophysics Data System (ADS)
Birkel, S. D.; Maasch, K. A.; Oglesby, R. J.; Fulginiti, L.; Trindade, F.; Hays, C.
GCM ensembles for the IPCC AR4 indicate that by 2060 water and wind resources will change appreciably over the central and northeastern U.S. In order to investigate these possible changes on a scale relevant for agriculture and offshore wind-power planners, we produced 24 km downscale simulations using the Weather Research and Forecasting (WRF) model. Our simulations span the years 2006-2010 and 2056-2060 with boundary conditions supplied by CCSM4 (IPCC emissions scenario RCP 8.5). By calculating the difference between the simulated time periods we find: 1) ~10% decrease in total annual precipitation across the southern half of the Ogallala aquifer in the central U.S., and ~10% increase across the northeastern states; and 2) Minimal change in annual-average 10-meter wind strength across the study areas, but with significant changes seasonal values. Interrogation of the simulation results is ongoing, and a complete synthesis will be presented at the annual meeting.
Guilfoyle, R.A.; Smith, L.M.
A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.
The national assessment of shoreline change: a GIS compilation of vector cliff edges and associated cliff erosion data for the California coast
Hapke, Cheryl; Reid, David; Borrelli, Mark
The U.S. Geological Survey has generated a comprehensive data clearinghouse of digital vector cliff edges and associated rates of cliff retreat along the open-ocean California coast. These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Cliff erosion is a chronic problem along many coastlines of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of coastal cliff retreat. There is also a critical need for these data to be consistent from one region to another. One objective of this work is to a develop standard, repeatable methodology for mapping and analyzing cliff edge retreat so that periodic, systematic, and internally consistent updates of cliff edge position and associated rates of erosion can be made at a national scale. This data compilation for open-ocean cliff edges for the California coast is a separate, yet related study to Hapke and others, 2006 documenting shoreline change along sandy shorelines of the California coast, which is itself one in a series that includes the Gulf of Mexico and the Southeast Atlantic coast (Morton and others, 2004; Morton and Miller, 2005). Future reports and data compilations will include coverage of the Northeast U.S., the Great Lakes, Hawaii and Alaska. Cliff edge change is determined by comparing the positions of one historical cliff edge digitized from maps with a modern cliff edge derived from topographic LIDAR (light detection and ranging) surveys. Historical cliff edges for the California coast represent the 1920s-1930s time-period; the most recent cliff edge was delineated using data collected between 1998 and 2002. End-point rate calculations were used to evaluate rates of erosion between the two cliff edges. Please refer to our full report on cliff edge erosion along the California coastline at http://pubs.usgs.gov/of/2007/1133/ for additional information regarding methods and results (Hapke and others, 2007). Data in this report are organized into downloadable layers by region (Northern, Central and Southern California) and are provided as vector datasets with accompanying metadata. Vector cliff edges may represent a compilation of data from one or more sources and the sources used are included in the dataset metadata. This project employs the Environmental Systems Research Institute's (ESRI) ArcGIS as it's Geographic Information System (GIS) mapping tool and contains several data layers (shapefiles) that are used to create a geographic view of the California coast. The vector data form a basemap comprising polygon and line themes that include a U.S. coastline (1:80,000), U.S. cities, and state boundaries.
The Pollination of Trimenia moorei (Trimeniaceae): Floral Volatiles, Insect/Wind Pollen Vectors and Stigmatic Self-incompatibility in a Basal Angiosperm
Trimenia moorei (Oliv.) Philipson is an andromonoecious liane with >0�40�of the total flower buds maturing as bisexual flowers. Male and bisexual flowers are strongly scented with pollen, anther sacs and receptacle scars testing positively for volatile emissions. Scent analyses detect over 20 components. The major fatty acid derivative is 8-heptadecene, and 2-phenylethanol dominates the benzenoids. While hover-flies in the genera Melangyna and Triglyphus contact the stigma with their probosces, the stigma secretes no free-flowing, edible fluids. Copious pollen is the only edible reward consumed by hover-flies (Syprhidae), sawflies (Pergidae) and bees in the families Apidae, Colletidae and Halictidae. All these insects carried pollen of T. moorei on their heads, legs and thoraces and female bees in the genera Apis, Exoneura, Leioproctus and Lasioglossum stored pollen on their hind legs. Pollen traps also indicate that pollen is shed directly into the air, permitting wind pollination. When bisexual flower buds are bagged (isolated from insect foragers) on the liane then subjected to a series of hand-pollination experiments after perianth segments open, the structural analyses of pollen�carpel interactions indicate that T. moorei has a trichome-rich dry-type stigma with an early-acting self-incompatibility (SI) system. Bicellular pollen grains deposited on stigmas belonging to the same plant germinate but fail to penetrate intercellular spaces, while grains deposited following cross-pollination reach the ovule within 24�h. Fluorescence analyses of 76 carpels collected at random from unbagged (open-pollinated) flowers on five plants indicates that at least 64�% of carpels are cross-pollinated in situ. Trimenia moorei is the first species within the ANITA group, and second within reilictual-basal angiosperm lineages, to exhibit stigmatic SI in combination with dry-type stigma and bicellular pollen, a condition once considered to be atypical for angiosperms as a whole but now known to be present in numerous taxa. PMID:12930730
The divergent wind component in data sparse tropical wind fields�
Snyder, Bruce Alan
. Poisson equation solver d. Evaluation of stresmfunction/velocity potential algorithms e. Computing divergent and nondivergent winds. . . . f. Analydcal studies of the divergent wind component g. Aliasing of divergence estimates CHAPTER VI RESULTS... AND DISCUSSION a. Methods of computing stresmfunction and velocity potential 14 30 33 36 36 Table of Contents (Continued) Page b. Analysis of Sangster's method c. Manipulation of divergent wind component fields d. Time continuity e. Vector error...
Three-dimensional wind profiling of offshore wind energy areas with airborne Doppler lidar
NASA Astrophysics Data System (ADS)
Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.
A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-?m wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.
NASA Technical Reports Server (NTRS)
Gray, Robert M.
During the past ten years Vector Quantization (VQ) has developed from a theoretical possibility promised by Shannon's source coding theorems into a powerful and competitive technique for speech and image coding and compression at medium to low bit rates. In this survey, the basic ideas behind the design of vector quantizers are sketched and some comments made on the state-of-the-art and current research efforts.
Hot gas ingestion test results of a two-poster vectored thrust concept with flow visualization in the NASA Lewis 9- x 15-foot low speed wind tunnel
NASA Technical Reports Server (NTRS)
Johns, Albert L.; Neiner, George; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.
A 9.2 percent scale Short Takeoff and Vertical Landing (STOVL) hot gas ingestion model was designed and built by McDonnell Douglas Corporation (MCAIR) and tested in the Lewis Research Center 9 x 15 foot Low Speed Wind Tunnel (LSWT). Hot gas ingestion, the entrainment of heated engine exhaust into the inlet flow field, is a key development issure for advanced short takeoff and vertical landing aircraft. Flow visualization from the Phase 1 test program, which evaluated the hot ingestion phenomena and control techniques, is covered. The Phase 2 test program evaluated the hot gas ingestion phenomena at higher temperatures and used a laser sheet to investigate the flow field. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/life improvement devices (LIDs) which reduced the hot gas ingestion. The model support system had four degrees of freedom - pitch, roll, yaw, and vertical height variation. The model support system also provided heated high-pressure air for nozzle flow and a suction system exhaust for inlet flow. The test was conducted at full scale nozzle pressure ratios and inlet Mach numbers. Test and data analysis results from Phase 2 and flow visualization from both Phase 1 and 2 are documented. A description of the model and facility modifications is also provided. Headwind velocity was varied from 10 to 23 kn. Results are presented over a range of nozzle pressure ratios at a 10 kn headwind velocity. The Phase 2 program was conducted at exhaust nozzle temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. The results reported are for nozzle exhaust temperatures up to 1160 R. These results will contain the compressor face pressure and temperature distortions, the total pressure recovery, the inlet temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane contours, the model airframe heating, and the location of the ground flow separation.
Retrospection of recent 30-year changes in the process of soil wind erosion in the Luanhe River Source Area of North China using Cesium137
Zhi-fan Chen; Ye Zhao; Jie-juan Qiao; Qing Zhang; Yu-en Zhu; Cui-hua Xu
The Luanhe River Source Area belongs to typical semi-arid, agro-pastoral ecotone of North China. It is very important for the prevention and treatment of soil erosion in North China to analyze and evaluate quantitatively the recent 30-year changes in the process of soil wind erosion in this area. Based on long field observations, soil samples from different depths in a
Pan evaporation and wind run decline in the Cape Floristic Region of South Africa (1974�2005): implications for vegetation responses to climate change
M. Timm Hoffman; Michael D. Cramer; Lindsey Gillson; Michael Wallace
In many regions of the world, increasing temperatures in recent decades are paradoxically associated with declining pan evaporation,\\u000a but evidence is sparse for this trend from the southern hemisphere in general and sub-Saharan Africa in particular. In this\\u000a study, we examined changes in pan evaporation and four other meteorological variables (rainfall, wind run, temperature and\\u000a vapour pressure deficit) at 20
A review of thrust-vectoring schemes for fighter applications
NASA Technical Reports Server (NTRS)
Berrier, B. L.; Re, R. J.
This paper presents a review of thrust vectoring schemes for advanced fighter applications. Results are presented from wind tunnel and system integration studies on thrust vectoring nozzle concepts. Vectoring data are presented from wind tunnel tests of axisymmetric C-D (convergent-divergent) and nonaxisymmetric wedge, C-D, single ramp and USB (upper-surface blowing) nozzle concepts. Results from recent airframe/nozzle integration studies on the impact of thrust vectoring on weight, cooling and performance characteristics are discussed. This review indicates that the aircraft designer has, at his disposal, a wide range of thrust vectoring schemes which offer potential for added or improved aircraft capability.
ERIC Educational Resources Information Center
Robelen, Erik W.
Five weeks after Katrina landed in Louisiana, Bonnabel and 78 other Jefferson Parish schools were welcoming students back--and far sooner than many had expected. The worst damage in Louisiana from Hurricane Katrina did not come to Jefferson Parish. That distinction was reserved for portions of New Orleans, as well as St. Bernard Parish, where�
ERIC Educational Resources Information Center
Reisser, Linda
The second edition of "Education and Identity" (Chickering & Reisser, 1993), updating Chickering's 1969 theory, describes institutional influences and broad changes in students as they move through higher education. The seven revised vectors are summarized in this article, and current issues related to the updated theory are discussed. (JBJ)
The interacting winds of Eta Carinae: Observed forbidden line changes and the Forbidden Blue(-Shifted) Crab
NASA Astrophysics Data System (ADS)
Gull, Theodore R.; Madura, Thomas; Corcoran, Michael F.; Teodoro, Mairan; Richardson, Noel; Hamaguchi, Kenji; Groh, Jose H.; Hillier, Desmond John; Damineli, Augusto; Weigelt, Gerd
The massive binary, Eta Carinae (EC), produces such massive winds that strong forbidden line emission of singly- and doubly-ionized iron traces wind-wind interactions from the current cycle plus fossil interactions from one, two and three 5.54-year cycles ago.With an eccentricity of >0.9, the >90 solar mass primary (EC-A) and >30 solar mass secondary (EC-B) approach to within 1.5 AU during periastron and recede to nearly 30 AU across apastron. The wind-wind structures move outward driven by the 420 km/s primary wind interacting with the ~3000 km/s secondary wind yielding partially-accelerated compressed primary wind shells that are excited by mid-UV from EC-A and in limited lines of sight, FUV from EC-B.These structures are spectroscopically and spatially resolved by HST's Space Telescope Imaging Spectrograph. At critical binary phases, we have mapped the central 2'x2' region in the light of [Fe III] and [Fe II] with spatial resolution of 0.12' and velocity resolution of 40 km/s.1) The bulk of forbidden emission originates from the large cavity northwest of EC and is due to ionization of massive ejecta from the 1840s and 1890s eruptions. The brightest clumps are the Weigelt Blobs C and D, but there are additionally multiple, fainter emission clumps. Weigelt B appears to have faded.2) Three concentric, red-shifted [FeII] arcs expand at ~470 km/s excited by mid-UV of EC-A.3) The structure of primarily blue-shifted [Fe III] emission resembles a Maryland Blue Crab. The claws appear at the early stages of the high-excitation recovery from the periastron passage, expand at radial velocities exceeding the primary wind terminal velocity, 420 km/s and fade as the binary system approaches periastron with the primary wind enveloping the FUV radiation from EC-B.4) All [Fe III] emission faded by late June 2014 and disappeared by August 2, 2014, the beginning of periastron passage.Comparisons to HST/STIS observations between 1998 to 2004.3 indicate long-term fading of [Fe II]. Likewise, Na D emission has faded. 3D hydro/radiative models suggest a small decrease (< factor of 2) in primary mass loss rate to be the cause.
Correlation of prefrontal cortical activation with changing vehicle speeds in actual driving: a vector-based functional near-infrared spectroscopy study
Yoshino, Kayoko; Oka, Noriyuki; Yamamoto, Kouji; Takahashi, Hideki; Kato, Toshinori
Traffic accidents occur more frequently during deceleration than during acceleration. However, little is known about the relationship between brain activation and vehicle acceleration because it has been difficult to measure the brain activation of drivers while they drive. In this study, we measured brain activation during actual driving using vector-based functional near-infrared spectroscopy. Subjects decelerated from 100 to 50 km/h (speed reduction task) and accelerated from 50 to 100 km/h (speed increase task) while driving on an expressway, in the daytime and at night. We examined correlations between average vehicle acceleration in each task and five hemodynamic indices: changes in oxygenated hemoglobin (?oxyHb), deoxygenated hemoglobin (?deoxyHb), cerebral blood volume (?CBV), and cerebral oxygen exchange (?COE); and the phase angle k (degrees) derived from the other hemoglobin (Hb) indices. ?oxyHb and ?CBV reflect changes in cerebral blood flow, whereas ?deoxyHb, ?COE, and k are related to variations in cerebral oxygen metabolism. Most of the resulting correlations with specific brain sites, for all the indices, appeared during deceleration rather than during acceleration. Faster deceleration resulted in greater increases in ?deoxyHb, ?COE, and k in the prefrontal cortex (r < ?0.5, p < 0.01), in particular, in the frontal eye field, and at night, it also resulted in greater decreases in ?oxyHb and ?CBV in the prefrontal cortex and in the parietal lobe (r > 0.4, p < 0.01), suggesting oxygen metabolism associated with transient ischemic changes. Our results suggest that vehicle deceleration requires more brain activation, focused in the prefrontal cortex, than does acceleration. From the standpoint of the indices used, we found that simultaneous analysis of multiple hemodynamic indices was able to detect not only the blood flow components of hemodynamic responses, but also more localized frontal lobe activation involving oxygen metabolism. PMID:24399953
New techniques in 3D scalar and vector field visualization
Max, N.; Crawfis, R.; Becker, B.
At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ``splatting`` scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ``flow volume`` of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity.
Winds of Change: The Physics of Accretion, Ejection, and X-ray Variability in GRS1915+105
NASA Astrophysics Data System (ADS)
Neilsen, Joseph
In the last twenty years, even as multiwavelength observations of black hole X-ray binaries have led to major advances, the microquasar GRS 1915+105 has continually challenged our understanding of the physics of accretion and ejection. With its relativistic jets, ionized winds, and myriad states of rapid, extreme variability, this remarkable black hole has been alternately seen as the black sheep of X-ray binaries and a Rosetta stone for black hole astrophysics. In this talk, I will present our efforts to use a decade of high-resolution X-ray spectroscopy of GRS 1915+105 to shed light on the processes that regulate its erratic behavior. I will highlight in particular the role of accretion disk winds on time scales ranging from seconds to years. Drawing on recent results, I will discuss the broader implications of these massive winds for the physics of inflows and outflows around black holes.
Amazonian malaria: Asymptomatic human reservoirs, diagnostic challenges, environmentally-driven changes in mosquito vector populations, and the mandate for sustainable control strategies
da Silva-Nunes, M�nica; Moreno, Marta; Conn, Jan E.; Gamboa, Dionicia; Abeles, Shira; Vinetz, Joseph M.; Ferreira, Marcelo U.
Across the Americas and the Caribbean, nearly 561,000 slide-confirmed malaria infections were reported officially in 2008. The nine Amazonian countries accounted for 89% of these infections; Brazil and Peru alone contributed 56% and 7% of them, respectively. Local populations of the relatively neglected parasite P. vivax, which currently accounts for 77% of the regional malaria burden, are extremely diverse genetically and geographically structured. At a time when malaria elimination is placed on the public health agenda of several endemic countries, it remains unclear why malaria proved so difficult to control in areas of relatively low levels of transmission such as the Amazon Basin. We hypothesize that asymptomatic parasite carriage and massive environmental changes that affect vector abundance and behavior are major contributors to malaria transmission in epidemiologically diverse areas across the Amazon Basin. Here we review available data supporting this hypothesis and discuss their implications for current and future malaria intervention policies in the region. Given that locally generated scientific evidence is urgently required to support malaria control interventions in Amazonia, we briefly describe the aims of our current field-oriented malaria research in rural villages and gold-mining enclaves in Peru and a recently opened agricultural settlement in Brazil. PMID:22015425
Markus Weinhardt; Wayne Luk
This paper presents pipeline vectorization, amethod for synthesizing hardware pipelines based on softwarevectorizing compilers. The method improves eciencyand ease of development of hardware designs, particularlyfor users with little electronics design experience. We proposeseveral loop transformations to customize pipelinesto meet hardware resource constraints, while maximizingavailable parallelism. For run-time recongurable systems,we apply hardware specialization to increase...
Long, David G.
THE WAVENUMBER SPECTRA OF SCATTEROMETER-DERIVED WINDS D. G . Long and D. D. Luke Electrical Spaceborne scatterometers are the only proven method for global all-weather measurement of vector winds/seainteraction where the time variability of the surface wind field and the wind stress curl drive the ocean; hence
APPENDIX D. VECTOR ANALYSIS 1 Vector Analysis
Callen, James D.
APPENDIX D. VECTOR ANALYSIS 1 Appendix D Vector Analysis The following conventions are used in this appendix and throughout the book: f, g, , are scalar functions of x, t; A, B, C, D are vector functions of x, t; A = |A| A � A is the magnitude or length of the vector A; ^eA A/A is a unit vector
Comparison of the response of doubly fed and fixed-speed induction generator wind turbines to changes in network frequency
J. Ekanayake; N. Jenkins
Synchronous and fixed-speed induction generators release the kinetic energy of their rotating mass when the power system frequency is reduced. In the case of doubly fed induction generator (DFIG)-based wind turbines, their control system operates to apply a restraining torque to the rotor according to a predetermined curve with respect to the rotor speed. This control system is not based
Long-term changes in solar wind elemental and isotopic ratios: A compairosn of two lunar ilmenites of different antiquities
R. H. Becker; R. O. Pepin
An ilmenite separate from lunar regolith breccia 79035, a sample presumed to have been exposed to solar wind more than 2 Ga ago, was analyzed for noble gas and nitrogen elemental and isotopic abundances by stepwise oxidation and pyrolysis. The gases appear to be distributed between two distinct reservoirs in the ilmenite, defined by release patterns and isotopic considerations. One
A Soft Vector Processor" Aaron Severance
Lemieux, Guy
VENICE: A Soft Vector Processor" Aaron Severance Advised by Prof. Guy Lemieux Zhiduo Liu, Chris Chou, Jason Yu, Alex Brant, Maxime Perreault, Chris Eagleston vector blox The University of British sequential code #12;6 Soft Vector Processor � Change algorithm � same RTL, just recompile software � Simple
The Probability Distribution of Sea Surface Wind Speeds. Part I: Theory and SeaWinds Observations
Monahan, Adam Hugh
The Probability Distribution of Sea Surface Wind Speeds. Part I: Theory and SeaWinds Observations expressions for the probability distribution of w in terms of the mean and standard deviation of the vector of the probability distribution of sea surface wind speeds play a central role in a number of problems in meteorology
DSCOVR High Time Resolution Solar Wind Measurements
NASA Technical Reports Server (NTRS)
Szabo, Adam
The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.
Southern Ocean Winds and Precipitation at the LGM: The Influence of State Dependency and Sea Surface Changes on CMIP5-PMIP3 Results
NASA Astrophysics Data System (ADS)
Sime, Louise; Hodgson, Dominic; Bracegirdle, Tom; Allen, Claire; Stephen, Roberts; Perren, Bianca
One hypothesis to explain the apparent tight coupling of deglacial atmospheric CO2 and Antarctic temperature is latitudinal shifts in the Southern Ocean westerly wind belt: shifts could drive changes in the ocean CO2 inventory. PMIP2 and PMIP3 models show considerable disagreement in their simulation of deglacial, 21 ky to 0 ky, Southern Ocean wind changes. This is despite nearly all CMIP5 models exhibiting a poleward shift and all models a strengthening of the surface jet following from 1900 to 2100, following the RCP8.5 scenario. Understanding what drives modelled wind changes, and the reasons for inter-model inconsistencies, should help our understanding of large changes in past CO2 and climate. We find that that jet position is strongly related to the sea ice edge latitude in PMIP3-CMIP5 simulations. An equatorwards shift in the sea ice edge correlates with a poleward shift in the jet latitude (r ~ -0.9). The relationship is strongest for 850 hPa winds, however similar results are obtained using 1000 hPa and ?U. A 1� difference in the sea ice edge suggests a -0.8� shift in the 850 hPa jet. However this applies only to models which have jets which are at a realistic latitude at 0 ky; if the 0 ky modelled jet sits equatorward of 47�S this relationship does not apply. If we look at the relationship between Southern Ocean sea surface temperature changes and jet shifts, a cooling of -1 K between 0 to 21 ky over the Gersonde et al. (2005) Southern Ocean compilation locations results in a 3.0� poleward shift in the 850 hPa jet (r = 0.83; n=5). The ensemble of present day CMIP5 model run data show an equatorward bias of 3.3� in the ensemble mean position of the surface zonal mean jet. We thus also calculate the impact of initial jet position, or state, dependency for Southern Ocean jet shifts and intensity changes across the various oceanic sectors. We find that state dependency explains up to 56% of the 0 to 21 ky jet shifts in the Atlantic (r=-0.75, N=9, for ?U), and 41% in the Indian Ocean (r = -0.64, N = 9, for ?U). State dependency is much weaker in the Pacific; here any influence is negligible. We generally find state dependence stronger for ?U than for the 850 hPa winds. For the whole of the Southern Ocean, the variance explained by state dependency is 38% (r = -0.62, N = 9, for ?U). Finally we also find that state dependency has a large influence on the simulation of past observed moisture changes. In the majority of cases model-data agreements at 21 ky are highly dependent on the jet position at 0 ky, indicating that state dependence is also critical in determining model-data moisture agreements. This finding also has implications for the calculation of Southern Ocean buoyancy forcing during the deglacial.
Dengue Vectors and their Spatial Distribution
Higa, Yukiko
The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133
representing the wind field in the lowest 4 km. Results show that changes in the large-scale wind pattern, as seen at 850 mb, can explain differences in the sea breeze circulation. Onshore flow leads to a faster moving sea breeze front whereas light opposing...
Seasonal changes in estuarine dissolved organic matter due to variable flushing time and wind-driven mixing events
NASA Astrophysics Data System (ADS)
Dixon, Jennifer L.; Osburn, Christopher L.; Paerl, Hans W.; Peierls, Benjamin L.
This study examined the seasonality of dissolved organic matter (DOM) sources and transformations within the Neuse River estuary (NRE) in eastern North Carolina between March 2010 and February 2011. During this time, monthly surface and bottom water samples were collected along the longitudinal axis of the NRE, ranging from freshwater to mesohaline segments. The monthly mean of all surface and bottom measurements made on collected samples was used to clarify larger physical mixing controls in the estuary as a whole. By comparing monthly mean trends in DOM and chromophoric dissolved organic matter (CDOM) properties in surface and bottom waters during varying hydrological conditions, we found that DOM and CDOM quality in the NRE is controlled by a combination of discharge, wind speed, and wind direction. The quality of DOM was assessed using C:N ratios, specific ultraviolet absorption at 254�nm (SUVA254), the absorption spectral slope ratio (SR), and the humification (HIX) and biological (BIX) indices from fluorescence. The NRE reflects allochthonous sources when discharge and flushing time are elevated at which times SUVA254 and HIX increased relative to base flow. During periods of reduced discharge and long flushing times in the estuary, extensive autochthonous production modifies the quality of the DOM pool in the NRE. This was evidenced by falling C:N values, and higher BIX and SR values. Lastly, a combination of increased wind speed and shifts in wind direction resulted in benthic resuspension events of degraded, planktonic OM. Thus, the mean DOM characteristics in this shallow micro-tidal estuary can be rapidly altered during episodic mixing events on timescales of a few weeks.
Changes in Sea-Level Pressure over South Korea Associated with High-Speed Solar Wind Events
Cho, Il-Hyun; Marubashi, Katsuhide; Kim, Yeon-Han; Park, Young-Deuk; Chang, Heon-Young
We explore a possibility that the daily sea-level pressure (SLP) over South Korea responds to the high-speed solar wind event. This is of interest in two aspects: First, if there is a statistical association this can be another piece of evidence showing that various meteorological observables indeed respond to variations in the interplanetary environment. Second, this can be a very crucial observational constraint since most models proposed so far are expected to preferentially work in higher latitude regions than the low latitude region studied here. We have examined daily solar wind speed ${\\rm V}$, daily SLP difference ${\\rm \\Delta SLP}$, and daily ${\\rm \\log(BV^{2})}$ using the superposed epoch analysis in which the key date is set such that the daily solar wind speed exceeds 800 ${\\rm kms^{-1}}$. We find that the daily ${\\rm \\Delta SLP}$ averaged out of 12 events reaches its peak at day +1 and gradually decreases back to its normal level. The amount of positive deviation of ${\\rm \\Delta SLP}$ is +2.5 hPa...
WIND ENERGY Wind Energ. 2013; 00:112
WIND ENERGY Wind Energ. 2013; 00:1�12 DOI: 10.1002/we RESEARCH ARTICLE Model predictive control. We use the turbine inertia as an additional energy storage device, by varying its speed over time. The simulation results using real wind data demonstrate the ability to reject the disturbances from fast changes
NASA Astrophysics Data System (ADS)
A �coherent and sustained program� of improved radar detection of weather, pilot training, and better communication between pilots and air controllers can greatly reduce the risk of wind shear to airplanes landing or taking off, according to a National Research Council (NRC) committee.Wind shear, characterized by winds rapidly changing direction and speed, has caused several serious accidents in recent years; among the most notable is the July 8, 1982, crash of a Pan American World Airlines jetliner at the New Orleans International Airport, which killed 153 persons. Following the accident, Congress directed the Federal Aviation Administration (FAA) to contract with the NRC to study wind shear.
Heat transfer phase change paint test (OH-42) of a Rockwell International SSV orbiter in the NASA/LRC Mach 8 variable density wind tunnel
NASA Technical Reports Server (NTRS)
Jones, R.; Creel, T. R., Jr.; Lawing, P.; Quan, M.; Dye, W.; Cummings, J.; Gorowitz, H.; Craig, C.; Rich, G.
Phase change paint tests of a Rockwell International .00593-scale space shuttle orbiter were conducted in the Langley Research Center's Variable Density Wind Tunnel. The test objectives were to determine the effects of various wing/underbody configurations on the aerodynamic heating rates and boundary layer transition during simulated entry conditions. Several models were constructed. Each varied from the other in either wing cuff radius, airfoil thickness, or wing-fuselage underbody blending. Two ventral fins were glued to the fuselage underside of one model to test the interference heating effects. Simulated Mach 8 entry data were obtained for each configuration at angles of attack ranging from 25 to 40 deg, and a Reynolds number variation of one million to eight million. Elevon, bodyflap, and rudder flare deflections were tested. Oil flow visualization and Schlieren photographs were obtained to aid in reducing the phase change paint data as well as to observe the flow patterns peculiar to each configuration.
Technology Transfer Automated Retrieval System (TEKTRAN)
In wind-driven rains, variations in raindrop trajectory and frequency are highly expected due to the changes in the angle of raindrop incidence. This paper presents experimental data obtained on the effects of horizontal wind velocity on physical raindrop impact and rainsplash detachment. In a wind ...
Vectors of rickettsiae in Africa.
Bitam, Idir
Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. PMID:23168053
Control of parallel multi-converters for permanent magnet wind power generation systems
Zhuang Xu; G. Li; Dianguo Xu
This paper proposes a control strategy for megawatt-level direct-drive wind energy conversion systems based on permanent magnet synchronous generators (PMSG). In the paper, a peak current model of zero-sequence current is derived and analyzed. The parallel-operation controllers are designed to restrain reactive power circulation and beat-frequency zero-sequence currents caused by discontinuous space-vector modulation (SVM). The control scheme does not change
Hanford Site peak gust wind speeds
Ramsdell, J.V.
Peak gust wind data collected at the Hanford Site since 1945 are analyzed to estimate maximum wind speeds for use in structural design. The results are compared with design wind speeds proposed for the Hanford Site. These comparisons indicate that design wind speeds contained in a January 1998 advisory changing DOE-STD-1020-94 are excessive for the Hanford Site and that the design wind speeds in effect prior to the changes are still appropriate for the Hanford Site.
An updated analysis of the ocean surface wind direction signal in passive microwave brightness temperatures
Thomas Meissner; Frank Wentz
We analyze the wind direction signal for vertically (v) and horizontally (h) polarized microwave radiation at 37 GHz, 19 GHz, and 11 GHz; and an Earth incidence angle of 53�. We use brightness temperatures from SSM\\/I and TMI and wind vectors from buoys and the QUIKSCAT scatterometer. The wind vectors are space and time collocated with the radiometer measurements. Water
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind erosion refers to the detachment, transport and deposition of sediment by wind. It is a dynamic, physical process where loose, dry, bare soils are transported by strong winds. Wind erosion is a soil degrading process that affects over 500 million ha of land worldwide and creates between 500 an...
Winds of Change: Expanding the Frontiers of Flight. Langley Research Center's 75 Years of Accomplishment, 1917-1992
NASA Technical Reports Server (NTRS)
Schultz, James
This commemorative volume highlights in pictures and text seventy five years of accomplishments of the Langley Research Center. The introductory matter features wind tunnels and their contribution to the development of aeronautics. A chronological survey details four different periods in Langley's history. The first period, 1917-1939, is subtitled 'Perfecting the Plane' which details Langley's contribution to early aeronautics with examples from specific aircraft. The second period, 1940-1957, focuses on the development of military aircraft during and after World War II. The third period, 1958-1969, tells the story of Langley's involvement with NASA and the satellite and Apollo era. The fourth period, entitled 'Charting New Courses: 1970-1992 and Beyond', treats various new topics from aerospace planes to Mars landing, as well as older topics such as the Space Shuttle and research spinoffs.
Solar wind plasma controlling magnetospheric coupling efficiency
T. I. Pulkkinen; M. Palmroth; K. Andreeova; T. V. Laitinen; R. L. McPherron
A wealth of new observational evidence add to the earlier understanding of solar wind - magnetosphere coupling the importance of solar wind speed and density. Statistical analysis shows that for the same electric field, events with higher solar wind speed cause larger AE disturbance than those with lower speed and higher magnetic field. Analysis of abrupt solar wind density changes
The Vector Product Introduction
Vickers, James
The Vector Product 9.4 Introduction In this section we describe how to find the vector product of two vectors. Like the scalar product its definition may seem strange when first met but the definition is chosen because of its many applications. When vectors are multiplied using the vector product the result
Adiabatic and nonadiabatic responses of the radiation belt relativistic electrons to the external changes in solar wind dynamic pressure and interplanetary magnetic field
NASA Astrophysics Data System (ADS)
Li, L.
By removing the influences of 'magnetopause shadowing' (r0>6.6RE) and geomagnetic activities, we investigated statistically the responses of magnetic field and relativistic (>0.5MeV) electrons at geosynchronous orbit to 201 interplanetary perturbations during 6 years from 2003 (solar maximum) to 2008 (solar minimum). The statistical results indicate that during geomagnetically quiet times (HSYM ?-30nT, and AE<200nT), ~47.3% changes in the geosynchronous magnetic field and relativistic electron fluxes are caused by the combined actions of the enhancement of solar wind dynamic pressure (Pd) and the southward turning of interplanetary magnetic field (IMF) (?Pd>0.4 nPa, and IMF Bz<0 nT), and only ~18.4% changes are due to single dynamic pressure increase (?Pd >0.4 nPa, but IMF Bz>0 nT), and ~34.3% changes are due to single southward turning of IMF (IMF Bz<0 nT, but |?Pd|<0.4 nPa). Although the responses of magnetic field and relativistic electrons to the southward turning of IMF are weaker than their responses to the dynamic pressure increase, the southward turning of IMF can cause the dawn-dusk asymmetric perturbations that the magnetic field and the relativistic electrons tend to increase on the dawnside (LT~00:00-12:00) but decrease on the duskside (LT~13:00-23:00). Furthermore, the variation of relativistic electron fluxes is adiabatically controlled by the magnitude and elevation angle changes of magnetic field during the single IMF southward turnings. However, the variation of relativistic electron fluxes is independent of the change in magnetic field in some compression regions during the enhancement of solar wind dynamic pressure (including the single pressure increases and the combined external perturbations), indicating that nonadiabatic dynamic processes of relativistic electrons occur there. Acknowledgments. This work is supported by NSFC (grants 41074119 and 40604018). Liuyuan Li is grateful to the staffs working for the data from GOES 8-12 satellites and OMNI database in CDAWeb.
Late Holocene changes in precipitation in northwest Tasmania and their potential links to shifts in the Southern Hemisphere westerly winds
Wehrli, Bernhard
Late Holocene changes in precipitation in northwest Tasmania and their potential links to shifts for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, 7000, Australia c British), northwest Tasmania. First, the relationship between scanning reflectance spectroscopy measurements
Solar wind eddies and the heliospheric current sheet
NASA Technical Reports Server (NTRS)
Suess, S. T.; Mccomas, D. J.; Bame, S. J.; Goldstein, B. E.
Ulysses has collected data between 1 and 5 AU during, and just following solar maximum, when the heliospheric current sheet (HCS) can be thought of as reaching its maximum tilt and being subject to the maximum amount of turbulence in the solar wind. The Ulysses solar wind plasma instrument measures the vector velocity and can be used to estimate the flow speed and direction in turbulent 'eddies' in the solar wind that are a fraction of an astronomical unit in size and last (have either a turnover or dynamical interaction time of) several hours to more than a day. Here, in a simple exercise, these solar wind eddies at the HCS are characterized using Ulysses data. This character is then used to define a model flow field with eddies that is imposed on an ideal HCS to estimate how the HCS will be deformed by the flow. This model inherently results in the complexity of the HCS increasing with heliocentric distance, but the result is a measure of the degree to which the observed change in complexity is a measure of the importance of solar wind flows in deforming the HCS. By comparison with randomly selected intervals not located on the HCS, it appears that eddies on the HCS are similar to those elsewhere at this time during the solar cycle, as is the resultant deformation of the interplanetary magnetic field (IMF). The IMF deformation is analogous to what is often termed the 'random walk' of interplanetary magnetic field lines.
ACARS wind measurements - An intercomparison with radiosonde, cloud motion and VAS thermally derived winds. [Communications, Addressing and Reporting System VISSR Atmospheric Sounder
NASA Technical Reports Server (NTRS)
Lord, R. J.; Menzel, W. P.; Pecht, L. E.
Statistical comparisons between winds measured by ACARS and winds obtained from radiosondes, geostationary satellite image cloud motions, and VAS are presented. Observations from three separate comparisons reveal over 60 percent of wind vector magnitude differences are within 9 m/s, and 70 percent of the directional differences are within 15 deg. The comparisons indicate that the ACARS system provides an independent source of wind data that complements other sources of wind data for constructing composite wind field analyses.
Generation of large-scale winds in horizontally anisotropic convection
von Hardenberg, J; Provenzale, A; Spiegel, E A
We simulate three-dimensional, horizontally periodic Rayleigh-B\\'enard convection between free-slip horizontal plates, rotating about a horizontal axis. When both the temperature difference between the plates and the rotation rate are sufficiently large, a strong horizontal wind is generated that is perpendicular to both the rotation vector and the gravity vector. The wind is turbulent, large-scale, and vertically sheared. Horizontal anisotropy, engendered here by rotation, appears necessary for such wind generation. Most of the kinetic energy of the flow resides in the wind, and the vertical turbulent heat flux is much lower on average than when there is no wind.
NSDL National Science Digital Library
Sharon Linamen
In this lesson students will learn the characteristics and appropriate use of vectors. They will find the magnitude and direction of vectors, they will add and subtract vectors and use an interactive website to practice what they have learned.
Solar wind proton deposition into the Martian atmosphere
Stephen H. Brecht
The direct impact of solar wind H + with the planet Mars is calculated using a three- dimensional hybrid particle code. The simulation results show a strong dependence on solar wind velocity and interplanetary magnetic field angle with the solar wind velocity vector. The energy fluxes calculated approach the solar EUV heating rates fxom photoelectrons and are found to be
SWE, a comprehensive plasma instrument for the WIND spacecraft
K. W. Ogilvie; D. J. Chornay; R. J. Fritzenreiter; F. Hunsaker; J. Keller; J. Lobell; G. Miller; J. D. Scudder; E. C. Sittler; R. B. Torbert; D. Bodet; G. Needell; A. J. Lazarus; J. T. Steinberg; J. H. Tappan; A. Mavretic; E. Gergin
The Solar Wind Experiment (SWE) on the WIND spacecraft is a comprehensive, integrated set of sensors which is designed to investigate outstanding problems in solar wind physics. It consists of two Faraday cup (FC) sensors; a vector electron and ion spectrometer (VEIS); a strahl sensor, which is especially configured to study the electron �strahl� close to the magnetic field direction;
Association of anthropogenic land use change and increased abundance of the Chagas disease vector Rhodnius pallescens in a rural landscape of Panama.
Gottdenker, Nicole L; Calzada, Jos� E; Salda�a, Az�el; Carroll, C Ronald
Anthropogenic disturbance is associated with increased vector-borne infectious disease transmission in wildlife, domestic animals, and humans. The objective of this study was to evaluate how disturbance of a tropical forest landscape impacts abundance of the triatomine bug Rhodnius pallescens, a vector of Chagas disease, in the region of the Panama Canal in Panama. Rhodnius pallescens was collected (n = 1,186) from its primary habitat, the palm Attalea butyracea, in five habitat types reflecting a gradient of anthropogenic disturbance. There was a high proportion of palms infested with R. pallescens across all habitat types (range = 77.1-91.4%). Results show that disturbed habitats are associated with increased vector abundance compared with relatively undisturbed habitats. Bugs collected in disturbed sites, although in higher abundance, tended to be in poor body condition compared with bugs captured in protected forest sites. Abundance data suggests that forest remnants may be sources for R. pallescens populations within highly disturbed areas of the landscape. PMID:21212205
NSDL National Science Digital Library
In this two part activity, learners work in pairs or individually to discover how vectoring the thrust from a jet engine affects movement of an airplane. In part one, learners construct an F-15 ACTIVE model with a balloon engine. In part two, learners conduct a series of experiments by changing the angle of the straw to control the direction of the thrust. This activity emphasizes the scientific method including prediction, observation, data collection, and analysis. This lesson plan includes background information, an extension and a sample worksheet.
Response of dominant wind wave fields to abrupt wind increase
NASA Astrophysics Data System (ADS)
Caulliez, Guillemette
Over the last decades, significant progress has been made in modelling wave field development by wind observed at sea, based on more elaborated numerical schemes and refined parametrizations of wind energy input and wave dissipation. In such models, the wind wave growth in space or time is generally governed by the average wind speed evaluated at one reference level and the natural wind speed variability is neglected. However, the impact of this assumption is not really known, mainly because of the lack of appropriate observations. To revisit this question, we report a detailed laboratory investigation aimed at describing the dominant wave field evolution resulting from an abrupt local wind speed increase. The experiments were conducted in the large Marseille-Luminy wind wave tank for moderate to high wind conditions. At 23 m fetch, a contraction of the wind tunnel section by a convergent profile created a spatial wind speed acceleration over a distance of about 2 m. Downwind, the wind speed, enhanced by a factor 1.4, was kept constant up to the end of the water tank. The wind wave field development induced by such a "wind gust" was investigated at successive fetches by wave probes and compared to those observed at similar fetches for homogeneous wind conditions. When wind increases, these observations first revealed no dramatic change in the evolution of the dominant spectral peak with fetch. The dominant wave energy which increases slowly for constant wind conditions, follows the wind speed but with a significant space lag. For well-established gravity wave fields, the space relaxation scales which describe this evolution do not depend noticeably on wind, all the curves collapse into a single one when wave quantities are normalized by their value observed just upstream the convergent profile. The wave growth rate observed for the new equilibrium state can be described by the Hasselman et al. (1973) relationship but with an "equivalent'' shorter fetch since, in such conditions, the dominant wave age decreases drastically. The evolution of the dominant spectral peak frequency has two more distinctive stages. First, there is a marked slowdown of the downshift immediately after the wind increase. This stage is then followed by a fast adjustment to the uniform wind regime corresponding to the new wind speed. A detailed analysis of the shape of the dominant peak however shows significant differences in the spectral energy distribution compared to those observed in homogeneous wind conditions. This finding suggests a deep change in the intrinsic features of wave groups. To characterize it quantitatively, the evolution of a number of statistical wave field properties as wave field skewness and kurtosis or the dominant wave breaking rate is examined and discussed within the framework of nonlinear wave theories.
Beisel, V.A.
An improved pump for lifting water from an underground source utilizes a wind motor for driving an oil-less air compressor eliminating oil contamination of ground water which is forced to the surface. The wind motor is movable to face the wind by means of a novel swivel assembly which also eliminates the formation and freezing of condensate within the airline from the compressor. The propeller blades of the wind motor and the tail section are formed from a pair of opposed convex air foil shaped surfaces which provide the propeller blades and the tail section with fast sensitivity to slight changes in wind direction and speed. A novel well tower for supporting the wind motor and compressor and for lifting the water from the underground source is an optional modification which requires no welding and eliminates the problem of condensate freezing in the airline going to the well. The wind driven air pump disclosed is lightweight, can be easily installed, is relatively inexpensive to produce and is virtually maintenance-free and capable of operating in winds exceeding 100 miles per hour.
Transmitting Vector Geospatial Data across the Internet
Barbara P. Buttenfield
Transmitting geospatial data via the Internet has become commonplace, and relies upon a raster data model that proves efficient\\u000a for imagery, orthophotography, and satellite data products. Internet transmission of vector geospatial data remains a challenge.\\u000a The content and geometry of vector data change with resolution, and this aspect of scale-dependence must be accounted for\\u000a in transmitting vector data across the
Microenvironmental changes and plant responses due to shading and wind deflectio by solar collectors: a simulation study
D. T. Patten; S. D. Smith
The potential microenvironmental changes at the ground surface beneath arrays of solar mirrors or collectors were investigated in a Sonoran Desert ecosystem, utilizing a simulated array of plywood panels. The simulated array consisted of twelve panels designed to exhibit a similar shape, tilt, and spacing as is expected to occur in heliostat fields of solar thermal facilities or in arrays
Spatio-Temporal Variability in Coastal Upwelling/Downwelling from Scatterometer Winds
NASA Astrophysics Data System (ADS)
Morey, S. L.
The decade-plus near-continuous record from satellite scatterometers provides indirect measurements of vector winds over the global ocean with sampling largely determined by the satellite orbits. This allows investigation of wind-driven ocean processes even at remote locations that are poorly sampled by in situ measurements. Global satellite wind products are used to produce a database of time series of upwelling indices, similar to those typically produced using data from coastal ocean observing systems, at all coastal locations over the Earth. This database is analyzed to study spatial and temporal variability of coastal upwelling and downwelling throughout the world ocean. The upwelling index is typically a proxy for upwelling/downwelling across the slope assuming a simple local mass balance to the offshore surface Ekman transport. However, along-shore variations in winds and shelf geometry perturb this simple local balance via shelf wave dynamics. In particular, cross-slope velocities downcoast (in a shelf wave propagation sense) of changes in the topographic gradient orientation may respond preferentially to a wind direction not oriented along local isobaths. Data from numerical models are analyzed to illustrate this point and to clarify the relation between upwelling/downwelling and local wind direction throughout the global coastal ocean that may allow improvement in wind-derived upwelling indices.
Impact of Wind on the LMP Market
Dale L. Osborn
The Midwest ISO (MISO) area has a projected supply of over 600,000 Mw of rated wind generation. Simulated LMP prices, production cost changes and area generation capacity factor changes for 15%, 20% and 25% wind energy penetration are presented in this paper. MISO has a little over a year of actual coordinated energy market LMP data and measured wind generation.
Probability distribution of wind retrieval error for the NASA scatterometer
NASA Technical Reports Server (NTRS)
Leotta, Daniel F.; Long, David G.
The NASA scatterometer (NSCAT) is a spaceborne scatterometer scheduled to be deployed in the mid-1990s. An analysis of the wind retrieval error distribution for wind estimates based on backscatter measurements made by the NSCAT instrument is presented. The results are based on an end-to-end simulation of the scatterometer instrument and data processing. In general, the distribution of the wind speed error, when normalized, is independent of the true wind speed and direction. The wind speed error can be characterized by a normal distribution. The wind direction error is independent of the true wind speed, but depends on the true wind direction. Details for wind vectors with true wind speeds from 3 m/s to 33 m/s and true wind directions from 0 to 360 deg are presented.
Effects of blade preset pitch/offset on curved-blade Darrieus vertical axis wind turbine performance
Klimas, P.C.; Worstell, M.H.
Current designs of curved-blade Darrieus vertical-axis wind turbines (VAWTs) have blades mounted in such a way that the position vector from the axis of rotation intersects the blade chord perpendicularly between the -25% and -50% chord points. This paper describes the effects on aerodynamic performance of the Sandia National Laboratories' (SNL) 5-m-dia turbine when its symmetrical cross-section blades are mounted such that the axis of rotation-blade chord position vector effects a normal intersection with the blade chord at points between -180% and +77% chord. These variations produce significant changes in cut-in tip-speed ratio, peak efficiency, and peak power.
NSDL National Science Digital Library
Integrated Teaching and Learning Program,
Students learn about wind energy by making a pinwheel to model a wind turbine. Just like engineers, they decide where and how their turbine works best by testing it in different areas of the playground.
NSDL National Science Digital Library
The Advanced Technology Environmental and Energy Center (ATEEC) provides this presentation on the career and technical aspects of wind energy. In addition to discussing careers in wind, the presentation covers the siting of wind turbines and some electricity basics. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.
Houston, Kevin
Liftable Vector Fields Kevin Houston Motivation Liftable Vector Fields Minimal Cross-cap The Three Families Applications Shameless Plug Vector Fields Liftable Over Stable Maps Kevin Houston Joint on Singularities in Generic Geometry and Applications, Valencia, Spain 2009 #12;Liftable Vector Fields Kevin
A new statistical approach to extreme wind speeds in France
C. Sacr�; J. M. Moisselin; M. Sabre; J. P. Flori; B. Dubuisson
To analyze all wind data available in the French meteorological stations, to elaborate a new extreme wind speeds map, an homogenization tool is developed that allow the detection and the correction of breaks due to sensor change and modification of measurement environment. Breaks are detected on annual mean wind speed series. Daily maximal wind speed values for about 150 wind
Resultant of Forces (Addition of vectors)
NSDL National Science Digital Library
Walter Fendt
The representation is a java applet demonstrating the combination of multiple force vectors on a body into a single resultant force vector. The user can vary the number of single forces, change the sizes and directions of these forces and determine the total force exerted on the body.
Winds of change - a molecular outflow in NGC 1377?. The anatomy of an extreme FIR-excess galaxy
NASA Astrophysics Data System (ADS)
Aalto, S.; Muller, S.; Sakamoto, K.; Gallagher, J. S.; Mart�n, S.; Costagliola, F.
Aims: Our goal was to investigate the molecular gas distribution and kinematics in the extreme far-infrared (FIR) excess galaxy NGC 1377 and to address the nature and evolutionary status of the buried source. Methods: We used high- (0''65 � 0''52, (65 � 52 pc)) and low- (4''88 � 2''93) resolution SubMillimeter Array (SMA) observations to image the 12CO and 13CO 2-1 line emission. Results: We find bright, complex 12CO 2-1 line emission in the inner 400 pc of NGC 1377. The 12CO 2-1 line has wings that are tracing a kinematical component that appears to be perpendicular to the component traced by the line core. Together with an intriguing X-shape of the integrated intensity and dispersion maps, this suggests that the molecular emission of NGC 1377 consists of a disk-outflow system. Lower limits to the molecular mass and outflow rate are Mout(H2) > 1 � 107 M? and ? > 8 M? yr-1. The age of the proposed outflow is estimated to be 1.4 Myr, the extent to be 200 pc and the outflow speed to be Vout = 140 km s-1. The total molecular mass in the SMA map is estimated to Mtot(H2) = 1.5 � 108 M? (on a scale of 400 pc) while in the inner r = 29 pc the molecular mass is Mcore(H2) = 1.7 � 107 M? with a corresponding H2 column density of N(H2) = 3.4 � 1023 cm-2 and an average 12CO 2-1 brightness temperature of 19 K. 13CO 2-1 emission is found at a factor 10 fainter than 12CO in the low-resolution map while C18O 2-1 remains undetected. We find weak 1 mm continuum emission of 2.4 mJy with spatial extent less than 400 pc. Conclusions: Observing the molecular properties of the FIR-excess galaxy NGC 1377 allows us to probe the early stages of nuclear activity and the onset of feedback in active galaxies. The age of the outflow supports the notion that the current nuclear activity is young - a few Myr. The outflow may be powered by radiation pressure from a compact, dust enshrouded nucleus, but other driving mechanisms are possible. The buried source may be an active galactic nucleus (AGN) or an extremely young (1 Myr) compact starburst. Limitations on size and mass lead us to favor the AGN scenario, but additional studies are required to settle this question. In either case, the wind with its implied mass outflow rate will quench the nuclear power source within the very short time of 5-25 Myr. It is possible, however, that the gas is unable to escape the galaxy and may eventually fall back onto NGC 1377 again.
Wind Turbines Adaptation to the Variability of the Wind Field
NASA Astrophysics Data System (ADS)
Ulianov, Yuriy; Martynenko, Gennadii; Misaylov, Vitaliy; Soliannikova, Iuliia
WIND TURBINES ADAPTATION TO THE VARIABILITY OF THE WIND FIELD The subject of our scientific research is wind power turbines (WPT) with the horizontal axis which were now common in the world. Efficient wind turbines work is largely determined by non-stationarity of the wind field, expressed in its gustiness, the presence of vertical and horizontal shifts of wind speed and direction. At critical values of the wind parameters WPT has aerodynamic and mechanical overload, leading to breakdowns, premature wear and reduce the life of the wind turbine. To prevent accidents at the peak values of wind speed it is used the regulatory system of windwheels. WPT control systems provide a process orientation of the wind turbine rotor axis in the line of the mean wind. Wind turbines are also equipped with braking device used to protect against breakdowns when a significant increase in the wind. In general, all these methods of regulation are not always effective. Thus, in practice there may be situations when the wind speed is many times greater than the stated limit. For example, if there are microbursts in the atmospheric boundary layer, low-level wind shears caused by its gust front, storms, etc. It is required for a wind power turbine adaptation to intensive short-term wind impulses and considerable vertical wind shifts that the data about them shall be obtained ahead of time. To do this it is necessary to have the information on the real structure of the wind field in the area of the blade sweep for the minimum range against the wind that is determined by the mean speed and the system action time. The implementation of acoustic and laser traditional wind sounding systems is limited by ambient acoustic noise, by heavy rain, snowfall and by fog. There are free of these disadvantages the inclined radioacoustic sounding (IRASS) technique which works for a system of remote detection and control of wind gusts. IRASS technique is realized as low-potential Doppler pulse radar including combined RF-acoustic antenna installed coaxially with the gondola of the wind power turbine. The work of the technique is synchronized with rotation of blades to eliminate their shielding action. Dangerous in terms of dynamic strength is the wind load pulse, the rise time which is comparable with the period of the natural frequency of the wind turbine elements (blade, tower, rotor, etc.). The amplitude decay of resonant vibrations at critical values of the speed of rotation can be realized through the use of mechanical elastic supports with nonlinear artificial dampers. They have a high coefficient of resistance, but may cause self-excited oscillations. We propose the way to deal with raised vibration of wind turbine elements at the expense of short-term increase of damping in the range of critical rotary axis speeds or during impulsive effects of wind loadings (wind gusts). This is possible through the use of non-linear electromagnetic dampers or active magnetic bearings. Their feature is the possibility of varying the mechanical stiffness and damping properties by changing the electrical parameters of electromagnets. The controlling of these parameters is carried out by the control system (CS) with the information feedback on the spatial-temporal structure of the wind field obtained from IRASS. In the composition of the CS can also be included the rotational speed sensor of the WPT rotor. This approach to the adaptation of wind turbines will allow to reduce vibration and to perform early compensation of the load on their components, which arise under the wind gusts. In addition, corrections about the wind field obtained with IRASS, would increase the mean power of WPT.
Wind Power: Creating a Wind Generator
NSDL National Science Digital Library
Demetrius Lutz
This lesson challenges groups of learners to design and construct a wind generator with the most electrical output. The lesson focuses on the engineering design process and how it is used to identify a question (solve a problem), develop a design or change a design, test that design, observe and collect data, analyze that data, and finally, form a conclusion that can inform another round of design. In this activity, learners attempt to maximize the voltage obtained from a wind-driven turbine by conducting several experimental designs.
Numerical Calculations of Wind Flow in a Full-Scale Wind Test Facility
Oh, Chang H; Lacey, Jerry Mark
Numerical studies on wind flow around the Texas Tech University (TTU) Wind Engineering Research Field Laboratory (WERFL) building were conducted. The main focus of this paper is wind loads on the TTU building in the INEEL proposed Windstorm Simulation Center. The results are presented in the form of distributions of static pressure, dynamic pressure, pressure coefficients, and velocity vectors on the surface and the vicinity of the TTU building.
Numerical calculations of wind flow in a full-scale wind test facility
C.H. Oh; J.M. Lacey
Numerical studies on wind flow around the Texas Tech University (TTU) Wind Engineering Research Field Laboratory (WERFL) building were conducted. The main focus of this paper is wind loads on the TTU building in the INEEL proposed Windstorm Simulation Center. The results are presented in the form of distributions of static pressure, dynamic pressure, pressure coefficients, and velocity vectors on the surface and the vicinity of the TTU building.
Tropospheric Wind Measurements from Space: The SPARCLE Mission and Beyond
NASA Technical Reports Server (NTRS)
Kavaya, Michael J.; Emmitt, G. David
For over 20 years researchers have been investigating the feasibility of profiling tropospheric vector wind velocity from space with a pulsed Doppler lidar. Efforts have included theoretical development, system and mission studies, technology development, and ground-based and airborne measurements. Now NASA plans to take the next logical step towards enabling operational global tropospheric wind profiles by demonstrating horizontal wind measurements from the Space Shuttle in early 2001 using a coherent Doppler wind lidar system.
Shearing wind helicity and thermal wind helicity
NASA Astrophysics Data System (ADS)
Han, Y.; Wu, R. S.; Fang, J.
Helicity is defined as H = V . omega, where V and omega are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity (SWH). Dynamically, it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity (TWH), as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.
Analysis of extreme wind speed and wind gust for Hungary
NASA Astrophysics Data System (ADS)
Peline Nemeth, Csilla; Bartholy, Judit; Pongr�cz, Rita; Radics, Korn�lia
Homogenized wind speed (1975-2012) and wind gust data sets (1975-2013) were analysed in order to assess Hungarian wind climate trends, variability, frequency and intensity of extreme wind events reliably. Decreases in the annual mean wind speed were found in our former studies when using homogenised observed wind data. These results are consistent with reduced Pole to Equator temperature gradient in a warmer world. Question arises how a changing global climate affects regional and local wind extremes in Hungary. First, 10-metre wind speed from the ERA Interim reanalysis was compared to the station observations. The comparison is quite difficult due to the fact that the observed 10-metre wind speed is a point measurement, where variables of the ERA Interim reanalysis represent larger areas, at least the size of the grid box (0.5��0.5�) and are subject to the effects of a smoothly varying surface topography. Then, 0.1� horizontal resolution gridded wind speed data sets (CARPATCLIM) based on homogenized measured data series were used to estimate spatial and temporal distribution of extreme wind parameters for Hungary. The extreme values calculated from the observed and CARPATCLIM wind data sets are presented in this study. The annual daily maxima of wind speed and wind gust were fitted to the Generalized Extreme Value distribution at every station, which were used to estimate 50- and 100-year return values. Additionally, the threshold crossing technique was applied to evaluate the frequency occurrence and the trend of moderate and strong wind days at the stations for the recent past.
ValidWind applications: wind power prospecting, aerosol transport
NASA Astrophysics Data System (ADS)
Wilkerson, T.; Marchant, A.; Apedaile, T.; Scholes, D.; Simmons, J.; Bradford, B.
The ValidWind� system employs an XL200 laser rangefinder to track small, lightweight, helium-filled balloons (0.33 meters, 0.015 kg). We record their trajectories (range resolution 0.5 meters) and automatically produce local wind profiles in real time. Tracking range is enhanced beyond 2 km by applying retro-reflector tape to the balloons. Aerodynamic analysis shows that ValidWind balloon motion is well coupled to the local wind within relaxation times { 1 second, due to drag forces at subcritical Reynolds numbers Re < 2�105. Such balloons are Lagrangian sensors; i.e., they move with the wind as opposed to being fixed in space. In a field campaign involving many balloons, slight variations in ground level winds at launch lead to trajectory patterns that we analyze to derive 3D maps of the vertical and horizontal wind profiles downwind of the launch area. Field campaigns are focused on likely sites for wind power generation and on facilities from which airborne particulates are emitted. We describe results of wind measurements in Utah near the cities of Clarkston, Logan, and Ogden. ValidWind is a relatively inexpensive wind sensor that is easily and rapidly transported and deployed at remote sites. It is an ideal instrument for wind prospecting to support early decisions required, for example, in siting meteorology towers. ValidWind provides high-resolution, real time characterization of the average and changing 3D wind fields in which wind power turbines and other remote sensors must operate.
Electric car with solar and wind energy may change the environment and economy: A tool for utilizing the renewable energy resource
NASA Astrophysics Data System (ADS)
Liu, Quanhua
Energy and environmental issues are among the most important problems of public concern. Wind and solar energy may be one of the alternative solutions to overcome energy shortage and to reduce greenhouse gaseous emission. Using electric cars in cities can significantly improve the air quality there. Through our analyses and modeling on the basis of the National Centers for Environment Prediction data we confirm that the amount of usable solar and wind energy far exceeds the world's total energy demand, considering the feasibility of the technology being used. Storing the surplus solar and wind energy and then releasing this surplus on demand is an important approach to maintaining uninterrupted solar- and wind-generated electricity. This approach requires us to be aware of the available solar and wind energy in advance in order to manage their storage. Solar and wind energy depends on weather conditions and we know weather forecasting. This implies that solar and wind energy is predictable. In this article, we demonstrate how solar and wind energy can be forecasted. We provide a web tool that can be used by all to arrive at solar and wind energy amount at any location in the world. The tool is available at http://www.renewableenergyst.org. The website also provides additional information on renewable energy, which is useful to a wide range of audiences, including students, educators, and the general public.
Stage-specific binding of Leishmania donovani to the sand fly vector midgut is regulated by conformational changes in the abundant surface lipophosphoglycan
The life cycle of Leishmania parasites within the sand fly vector includes the development of extracellular promastigotes from a noninfective, procyclic stage into an infective, metacyclic stage that is uniquely adapted for transmission by the fly and survival in the vertebrate host. These adaptations were explored in the context of the structure and function of the abundant surface lipophosphoglycan (LPG) on Leishmania donovani promastigotes. During metacyclogenesis, the salient structural feature of L. donovani LPG is conserved, involving expression of a phosphoglycan chain made up of unsubstituted disaccharide-phosphate repeats. Two important developmental modifications were also observed. First, the size of the molecule is substantially increased because of a twofold increase in the number of phosphorylated disaccharide repeat units expressed. Second, there is a concomitant decrease in the presentation of terminally exposed sugars. This later property was indicated by the reduced accessibility of terminal galactose residues to galactose oxidase and the loss of binding by the lectins, peanut agglutinin, and concanavalin A, to metacyclic LPG in vivo and in vitro. The loss of lectin binding was not due to downregulation of the capping oligosaccharides as the same beta- linked galactose or alpha-linked mannose-terminating oligosaccharides were present in both procyclic and metacyclic promastigotes. The capping sugars on procyclic LPG were found to mediate procyclic attachment to the sand fly midgut, whereas these same sugars on metacyclic LPG failed to mediate metacyclic binding. And whereas intact metacyclic LPG did not inhibit procyclic attachment, depolymerized LPG inhibited as well as procyclic LPG, demonstrating that the ligands are normally buried. The masking of the terminal sugars is attributed to folding and clustering of the extended phosphoglycan chains, which form densely distributed particulate structures visible on fracture-flip preparations of the metacyclic surface. The exposure and subsequent masking of the terminal capping sugars explains the stage specificity of promastigote attachment to and release from the vector midgut, which are key events in the development of transmissible infections in the fly. PMID:7836922
Winds aloft statistical analysis in support of day of launch Shuttle systems evaluation
NASA Technical Reports Server (NTRS)
Adelfang, S. I.; Smith, O. E.; Batts, G. W.; Hill, C. K.
In connection with the development of the Meteorological Interactive Data Display System (MIDDS) for utilization by the Launch Systems Evaluation Advisory Team (LSEAT), requirements have been established to expand the pre-launch analysis of winds aloft for the Space Shuttle. Statistical analyses developed for the system include: comparison of pre-launch wind component profiles to wind component extremes at each altitude calculated from launch site historical data; conditional probability ellipses for wind vectors at a future time given the wind vector at an initial time; comparison of observed extreme wind shear and associated wind speed with launch site historical data utilizing the bivariate extreme value (Gumbel) distribution; estimation of extremes of wind speed or wind shear at a future time given the extremes of either variable at an initial time, utilizing the conditional extreme value distribution; power spectrum analysis for tracking wind perturbation energy in sequential pre-launch Jimsphere wind profiles.
NSDL National Science Digital Library
In this activity, students will set up a model forest using plastic bottles to observe changes caused by differences in wind speed and forest density. An extension to the activity will allow students to explore the concept of evapotranspiration. From this activity students will understand that living organisms in an ecosystem can have profound effects upon the local atmosphere, changes in vegetation can have profound effects upon wind speed, and models are useful to researchers in understanding the shaping of ecosystems. The teacher's guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.
Wind/Hybrid Electricity Applications
McDaniel, Lori
Wind energy is widely recognized as the most efficient and cost effective form of new renewable energy available in the Midwest. New utility-scale wind farms (arrays of large turbines in high wind areas producing sufficient energy to serve thousands of homes) rival the cost of building new conventional forms of combustion energy plants, gas, diesel and coal power plants. Wind energy is not subject to the inflationary cost of fossil fuels. Wind energy can also be very attractive to residential and commercial electric customers in high wind areas who would like to be more self-sufficient for their energy needs. And wind energy is friendly to the environment at a time when there is increasing concern about pollution and climate change. However, wind energy is an intermittent source of power. Most wind turbines start producing small amounts of electricity at about 8-10 mph (4 meters per second) of wind speed. The turbine does not reach its rated output until the wind reaches about 26-28 mph (12 m/s). So what do you do for power when the output of the wind turbine is not sufficient to meet the demand for energy? This paper will discuss wind hybrid technology options that mix wind with other power sources and storage devices to help solve this problem. This will be done on a variety of scales on the impact of wind energy on the utility system as a whole, and on the commercial and small-scale residential applications. The average cost and cost-benefit of each application along with references to manufacturers will be given. Emerging technologies that promise to shape the future of renewable energy will be explored as well.
Yeoman, D.R.
This patent describes a wind turbine. It comprises: a vertical axis rotor assembly coupled to a rotatable drive shaft for driving electrical power generating means; first wind deflector means for initially reflecting wind current into the rotor assembly; second wind deflector means to redirect the initially deflected wind current into the rotor assembly; and mounting means for mounting the first and second wind deflector means in the normal positions. The mounting means including an outer shaft through which the drive shaft extends and which is normally fixed with respect thereto. The outer shaft having at least one lower groove winding in one of a left-hand or right-hand direction, at least one lower groove constituting a first lower groove set, and at least one upper groove winding in the other of the left-hand or right-hand direction, at least one upper groove constituting a second upper groove set, and first lower and second upper connector rings coupled to the first and second wind deflector means respectively, and mounted on the outer shaft proximate to the first and second groove sets respectively. The first and second connector rings including guide means cooperating with at least one groove of the first and second groove sets respectively. The mounting means allowing at least one of the first and second wind deflector means to automatically move relative to each other and from its respective normal position when the velocity of the wind current exceeds a first predetermined value to increase the inter-deflector spacing and causing at least one of the first and second wind deflector means to automatically return to its respective normal position when the velocity of the wind current diminishes to a value below the first predetermined value.
VisibleWind: wind profile measurements at low altitude
NASA Astrophysics Data System (ADS)
Wilkerson, Tom; Bradford, Bill; Marchant, Alan; Apedaile, Tom; Wright, Cordell
VisibleWindTM is developing an inexpensive rapid response system, for accurately characterizing wind shear and small scale wind phenomena in the boundary layer and for prospecting suitable locations for wind power turbines. The ValidWind system can also collect reliable "ground truth" for other remote wind sensors. The system employs small (0.25 m dia.) lightweight balloons and a tracker consisting of an Impulse 200 XL laser rangefinder coupled to a PC for automated data recording. Experiments on balloon trajectories demonstrate that the laser detection of range (+/- 0.5 m), together with measured azimuth and altitude, is an inexpensive, convenient, and capable alternative to other wind tracking methods. The maximum detection range has been increased to 2200 meters using micro-corner-cube retroreflector tape on balloons. Low power LEDs enable nighttime tracking. To avoid large balloon gyrations about the mean trajectory, we use balloons having low ascent rates and subcritical Reynolds numbers. Trajectory points are typically recorded every 4 - 7 seconds. Atmospheric features observed under conditions of inversions or "light and variable winds" include abrupt onsets of shear at altitudes of 100-250 m, velocity changes of order 1-3 m/s within layers of 10-20 m thickness, and veering of the wind direction by 180 degrees or more as altitude increases from 300 to 500 m. We have previously reported comparisons of balloon-based wind profiles with the output of a co-located sodar. Even with the Impulse rangefinder, our system still requires a "man in the loop" to track the balloon. A future system enhancement will automate balloon tracking, so that laser returns are obtained automatically at 1 Hz. While balloon measurements of large-scale, high altitude wind profiles are well known, this novel measurement system provides high-resolution, real-time characterization of the fluctuating local wind fields at the bottom of the boundary layer where wind power turbines and other remote wind sensors must operate.
Ryan H. Wiser; Mark Bolinger; G. Barbose; A. Mills; A. Rosa; K. Porter; S. Fink; S. Tegen; W. Musial; F. Oteri; D. Heimiller; B. Rberts; K. Belyeu; R. Stimmel
The U.S. wind industry experienced a banner year in 2008, again surpassing even optimistic growth projections from years past. At the same time, the last year has been one of upheaval, with the global financial crisis impacting near-term growth prospects for the wind industry, and with federal policy changes enacted to push the industry towards continued aggressive expansion. This rapid
Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint
Hodge, B. M.; Shedd, S.; Florita, A.
This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.
Wind-Direction Effects on Urban-Type Flows
NASA Astrophysics Data System (ADS)
Claus, Jean; Coceal, O.; Thomas, T. Glyn; Branford, S.; Belcher, S. E.; Castro, Ian P.
Practically all extant work on flows over obstacle arrays, whether laboratory experiments or numerical modelling, is for cases where the oncoming wind is normal to salient faces of the obstacles. In the field, however, this is rarely the case. Here, simulations of flows at various directions over arrays of cubes representing typical urban canopy regions are presented and discussed. The computations are of both direct numerical simulation and large-eddy simulation type. Attention is concentrated on the differences in the mean flow within the canopy region arising from the different wind directions and the consequent effects on global properties such as the total surface drag, which can change very significantly�by up to a factor of three in some circumstances. It is shown that for a given Reynolds number the typical viscous forces are generally a rather larger fraction of the pressure forces (principally the drag) for non-normal than for normal wind directions and that, dependent on the surface morphology, the average flow direction deep within the canopy can be largely independent of the oncoming wind direction. Even for regular arrays of regular obstacles, a wind direction not normal to the obstacle faces can in general generate a lateral lift force (in the direction normal to the oncoming flow). The results demonstrate this and it is shown how computations in a finite domain with the oncoming flow generated by an appropriate forcing term (e.g. a pressure gradient) then lead inevitably to an oncoming wind direction aloft that is not aligned with the forcing term vector.
Evaluation of High Wind Speed Observations from Spaceborne and Airborne Ocean Wind Measurement Systems
NASA Astrophysics Data System (ADS)
Jelenak, Zorana; Chang, Paul; Soisuvarn, Seubsom; Alsweiss, Suleiman
It is very difficult to obtain high quality in-situ wind data in the high wind speed regimes (>17m/s). Winds measured by moored small-hulled buoys become increasingly low biased as wind speeds exceed 20 m/s. Ordinary ship reported winds are of poor quality in this high wind speed range, and the better-equipped research vessels rarely sample this wind regime. Finally, marine wind fields produced by numerical weather prediction (NWP) models, including even the products of the newer "reanalysis" projects, are notoriously biased low in severe storms. The best-suited candidates to assess the performance of new wind measurements are actually other spaceborne and airborne ocean wind vector instruments (such as ASCAT and WindSat) provided their performance in high wind speed regimes are well understood. The Indian Space Research Organization (ISRO) launched the OceanSat-2 satellite on 23 September 2009. Oceansat-2 is ISRO's second in a series of satellites dedicated to ocean research. OceanSat-2 carries a microwave radar scatterometer (OSCAT) capable of measuring the ocean surface vector winds. The OSCAT operates at Ku-band (13.515 GHz) scanning the earth surface conically at 20.5 rpm using dual-polarized pencil beams with an incidence angle 48.9 degree for the horizontally polarized (H-pol) beam and 57.6 degree for the vertically polarized (V-pol) beam resulting in a swath width of 1840 km. The orbit characteristics provide global ocean coverage wind retrievals within 29 orbits or 2 days. In the paper we will present validation of high wind estimates from OSCAT measurements processed by NOAA.
Yeoman, D.R.
A wind turbine is described comprising: a vertical axis rotor assembly coupled to a rotatable drive shaft for driving electrical power generating means; first wind deflector means mounted on the wind turbine normally positioned generally upwind and to one side of the rotor assembly for initially deflecting wind current into the rotor assembly and second wind deflector means mounted on the wind turbine normally positioned on another side of the rotor assembly to redirect the initially deflected wind current into the rotor assembly. The first and second wind deflector means are normally spaced from each other by a certain inter-deflector spacing; mounting means for mounting the first and second wind deflector means in the normal positions, the mounting means including an outer shaft through which the drive shaft extends and which is normally fixed with respect thereto. The outer shaft has an upwardly facing circumferentially extending shoulder formed therein including a first shoulder portion extending around a major portion of the circumference of the outer shaft and a pair of upwardly sloping portions which reet at an apex.
NSDL National Science Digital Library
A sub-page of the extremely informative VectorBase. This is a worldwide listing of malaria vectors divided into 12 geographic regions following the 1957 classic The Epidemiology and Control of Malaria by MacDonald.
Mark Cieliebak; Alexander Hall; Riko Jacob; Marc Nunkesser
We introduce a novel variant of the well known d-dimensional bin (or vector) packing problem. Given a sequence of non-negative d-dimensional vectors, the goal is to pack these into as few bins as possible. In the classical problem the bin size vector is given and the sequence can be partitioned arbi- trarily. We study a variation where the vectors have
J. Astola; P. Haavisto; Y. Neuvo
Two nonlinear algorithms for processing vector-valued signals are introduced. The algorithms, called vector median operations, are derived from two multidimensional probability density functions using the maximum-likelihood-estimate approach. The underlying probability densities are exponential, and the resulting operations have properties very similar to those of the median filter. In the vector median approach, the samples of the vector-valued input signal are
Quantification of shoreline change along Hatteras Island, North Carolina: Oregon Inlet to Cape Hatteras, 1978-2002, and associated vector shoreline data
Hapke, Cheryl J.; Henderson, Rachel E.
Shoreline change spanning twenty-four years was assessed along the coastline of Cape Hatteras National Seashore, at Hatteras Island, North Carolina. The shorelines used in the analysis were generated from georeferenced historical aerial imagery and are used to develop shoreline change rates for Hatteras Island, from Oregon Inlet to Cape Hatteras. A total of 14 dates of aerial photographs ranging from 1978 through 2002 were obtained from the U.S. Army Corp of Engineers Field Research Facility in Duck, North Carolina, and scanned to generate digital imagery. The digital imagery was georeferenced and high water line shorelines (interpreted from the wet/dry line) were digitized from each date to produce a time series of shorelines for the study area. Rates of shoreline change were calculated for three periods: the full span of the time series, 1978 through 2002, and two approximately decadal subsets, 1978�89 and 1989�2002.
G. Sobczyk
Ordinary Gibbs-Heaviside vector algebra is complexified to apply to spacetime. The resulting algebra is isomorphic to both the Pauli algebra, and to the algebra of complex quaternions. Each inertial system is distinguished by a rest frame of real vectors. The rudiments of a spacetime vector analysis are given.
Noga Alon; E. E. Bergmann; Don Coppersmith; Andrew M. Odlyzko
IntroductionLet K(n , d) denote the minimal k for which there exist 1 vectors v 1 , . . . , v k oflength n such that for any 1 vector w of length n, there is an i, 1 i k, such thatv i.w d, where v.w denotes the usual inner product of two vectors. Sincev.w n (mod 2)
NASA Technical Reports Server (NTRS)
Raymond, William H.
The equations describing the temporal and spatial behavior of the kinematic moisture and heat flux are described. In these nonlinear equations, the contribution by diabatic processes to the large-scale flux is composed of two parts. One part is associated with a Rayleigh damping term while the other arises from temporal and spatial changes in the pressure gradient term. It was found that the influence of diabatic processes on large-scale moisture fluxes depends greatly on the degree of balance between forcing and damping terms in the governing kinematic flux equations. The existence of a near balance requires a reduction in the large-scale horizontal geostrophic wind speed. Based on an examination of the moisture flux equations, it is argued that reductions in the large-scale horizontal wind speed observed within major cumulus cloud systems help conserve large-scale moisture fluxes. The deviation of the wind from geostrophic conditions is easily estimated for a near balanced state. This wind modification induces secondary vertical circulations that contribute to convergence, creating or supporting long-lived mesoscale flows. We believe this process to be a major supporter of the mesoscale circulations observed in severe storms and squall lines. In the tropics the wind modification has an antitriptic relationship. These diagnostic findings suggest possible modifications to the wind field in the application of a cumulus parameterization, and may be important in diabatic initialization of numerical weather prediction models.
NASA Technical Reports Server (NTRS)
Raymond, William H.
Equations describing the temporal and spatial behavior of the kinematic moisture and heat flux are introduced. In these nonlinear equations, the contribution by diabatic processes to the large-scale flux is composed of two parts. One part is associated with a Rayleigh damping term, while the other arises from temporal and spatial changes in the pressure gradient term. The influence of diabatic processes on the large-scale moisture fluxes depends greatly on the degree of balance between forcing and damping terms in the governing equations. The existence of a near balance requires a reduction in the large-scale horizontal geostrophic wind speed. From a scale analysis of the moisture flux equations it is argued that reductions in the large-scale horizontal wind speed, observed within major cumulus cloud systems, help conserve large-scale moisture fluxes. The deviation of the wind from geostrophic conditions is easily estimated. This wind modification induces secondary vertical circulations that contribute to the convergence, creating or supporting long-lived mesoscale flows. In the tropics the wind modification has an antitriptic relationship. These diagnostic findings suggest possible modifications to the wind field in the application of cumulus parameterization, and may be important in diabatic initialization of numerical weather prediction models.
The changing burden of malaria and association with vector control interventions in Zambia using district-level surveillance data, 2006�2011
Background Malaria control was strengthened in Zambia over the past decade. The two primary interventions for vector control are indoor residual spraying (IRS) and long-lasting insecticide-treated nets (LLINs). Using passive malaria surveillance data collected from 2006 to 2011 through the Zambian District Health Information System, the associations between increased coverage with LLINs and IRS and the burden of malaria in Zambia were evaluated. Methods National passive malaria surveillance data from 2006 to 2011 were analysed. A district-level, random-effects model with Poisson regression was used to explore the association between malaria cases and coverage with LLINs and IRS. Malaria cases and LLINs and IRS coverage were mapped to visualize spatiotemporal variation in malaria for each year. Results From 2006�2011, 24.6 million LLINs were distributed and 6.4 million houses were sprayed with insecticide. Coverage with LLINs was not uniformly distributed over the study period and IRS was targeted to central and southern districts where malaria transmission was low. LLIN coverage was associated with a reduction in malaria cases, although an increase in the number of malaria cases was reported in some districts over the study period. A high burden of malaria persisted in north-eastern Zambia, whereas a reduction in the number of reported malaria cases was observed in western and southern Zambia. Conclusion Enhanced and targeted interventions in north-eastern Zambia where the burden of malaria remains high, as well as efforts to sustain low malaria transmission in the south-west, will be necessary for Zambia to achieve the national goal of being malaria free by 2030. PMID:24289177
Population genetic structure of the malaria vector Anopheles funestus, in a recently re-colonized area of the Senegal River basin and human-induced environmental changes
Background Anopheles funestus is one of the major malaria vectors in tropical Africa. Because of several cycles of drought events that occurred during the 1970s, this species had disappeared from many parts of sahelian Africa, including the Senegal River basin. However, this zone has been re-colonized during the last decade by An. funestus, following the implementation of two dams on the Senegal River. Previous studies in that area revealed heterogeneity at the biological and chromosomal level among these recent populations. Methods Here, we studied the genetic structure of the newly established mosquito populations using eleven microsatellite markers in four villages of the Senegal River basin and compared it to another An. funestus population located in the sudanian domain. Results Our results presume Hardy Weinberg equilibrium in each An. funestus population, suggesting a situation of panmixia. Moreover, no signal from bottleneck or population expansion was detected across populations. The tests of genetic differentiation between sites revealed a slight but significant division into three distinct genetic entities. Genetic distance between populations from the Senegal River basin and sudanian domain was correlated to geographical distance. In contrast, sub-division into the Senegal River basin was not correlated to geographic distance, rather to local adaptation. Conclusions The high genetic diversity among populations from Senegal River basin coupled with no evidence of bottleneck and with a gene flow with southern population suggests that the re-colonization was likely carried out by a massive and repeated stepping-stone dispersion starting from the neighboring areas where An. funestus endured. PMID:22950576
Developing Wind Energy in the European Union
Kamil Kaygusuz
Wind energy is the fastest-growing electricity-generating technology. The wind energy targets set during the last decade have all been surpassed. New targets are proposed for 2010 and 2020, since the existing European Commission and European Wind Energy Association targets do not reflect the trends in the market. Climate change is a major challenge to sustainable development worldwide and is increasingly
Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region
Technology Transfer Automated Retrieval System (TEKTRAN)
Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic anim...
Changes in size and power available to miming transport equipment, combined with improved means of control involving leaking feeder radio and computers, demands a new look at the problem of mine winding and transport. This book covers the design and application of steel wire ropes to a variety of industrial applications along with the various pulleys and drums necessary. It
Heat transfer phase change paint tests of 0.0175-scale models (nos. 21-0 and 46-0) of the Rockwell International space shuttle orbiter in the AEDC tunnel B hypersonic wind tunnel (test OH25A)
NASA Technical Reports Server (NTRS)
Dye, W. H.
Tests were conducted in a hypersonic wind tunnel using various truncated space shuttle orbiter configurations in an attempt to establish the optimum model size for other tests examining body shock-wing leading edge interference effects. The tests were conducted at Mach number 8 using the phase change paint technique. A test description, tabulated data, and tracings of isotherms made from photographs taken during the test are presented.
Towards a Wind Energy Climatology at Advanced Turbine Hub-Heights: Preprint
M. Schwartz; D. Elliott
Measurements of wind characteristics over a wide range of heights up to and above 100 m are useful to: (1) characterize the local and regional wind climate; (2) validate wind resource estimates derived from numerical models; and (3) evaluate changes in wind characteristics and wind shear over the area swept by the blades. Developing wind climatology at advanced turbine hub
A recursive technique for adaptive vector quantization
NASA Technical Reports Server (NTRS)
Lindsay, Robert A.
Vector Quantization (VQ) is fast becoming an accepted, if not preferred method for image compression. The VQ performs well when compressing all types of imagery including Video, Electro-Optical (EO), Infrared (IR), Synthetic Aperture Radar (SAR), Multi-Spectral (MS), and digital map data. The only requirement is to change the codebook to switch the compressor from one image sensor to another. There are several approaches for designing codebooks for a vector quantizer. Adaptive Vector Quantization is a procedure that simultaneously designs codebooks as the data is being encoded or quantized. This is done by computing the centroid as a recursive moving average where the centroids move after every vector is encoded. When computing the centroid of a fixed set of vectors the resultant centroid is identical to the previous centroid calculation. This method of centroid calculation can be easily combined with VQ encoding techniques. The defined quantizer changes after every encoded vector by recursively updating the centroid of minimum distance which is the selected by the encoder. Since the quantizer is changing definition or states after every encoded vector, the decoder must now receive updates to the codebook. This is done as side information by multiplexing bits into the compressed source data.
Long-term impact of North African drought on mineral dust in the trade winds over the Atlantic Ocean and Caribbean: climate change implications
NASA Astrophysics Data System (ADS)
Prospero, J.; Lamb, P.
Aerosol measurements on Barbados, West Indies, over the period 1965-1998 show that trade winds often carry great quantities of African mineral dust. Over much of this period the Soudano-Sahel (SS) region in North Africa suffered from varying degrees of drought. At Barbados we observe large year-to-year variations in dust that are highly correlated with SS rainfall deficits. To gauge longer-term variability we estimate dust loads during past moist regimes using the Barbados correlation regression with SS rainfall data. In the reconstructed Barbados dust record between 1941 and 1998, the mean during the 1950s, a relatively moist phase in the SS, was four times lower than during the 1980's, a relatively dry phase. The years yielding the ten lowest mean May-September dust concentrations all occurred before 1966 and the mean for those years was 3.0 ?g m-3; the ten years with the highest means occurred after 1972 and the overall mean was 21.4 ?g m-3 an increase by a factor of 7. The dust variability over this period appears to be substantially greater than that of pollution aerosols in North America and Europe. These data demonstrate the extreme sensitivity of dust mobilization to climate change. Because dust is also believed to play a strong role in climate forcing processes, drought in North Africa can impact climate over large areas through the propagation of dust over thousands of km downstream, westward to the Caribbean and the eastern United States and north to Europe. Dust could also impact health in this region; during SS drought phases the concentration of fine dust over the Caribbean exceeds the US EPA standard for respirable particles.
Leithead, W E
From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented. PMID:17272245
Tropospheric Wind Profile Measurements with a Direct Detection Doppler Lidar
NASA Technical Reports Server (NTRS)
Gentry, Bruce M.; Li, Steven X.; Korb, C. Laurence; Chen, Huailin; Mathur, Savyasachee
Research has established the importance of global tropospheric wind measurements for large scale improvements in numerical weather prediction. In addition, global wind measurements provide data that are fundamental to the understanding and prediction of global climate change. These tasks are closely linked with the goals of the NASA Earth Science Enterprise and Global Climate Change programs. NASA Goddard has been actively involved in the development of direct detection Doppler lidar methods and technologies to meet the wind observing needs of the atmospheric science community. In this paper we describe a recently developed prototype wind lidar system using a direct detection Doppler technique for measuring wind profiles from the surface through the troposphere. This system uses a pulsed ND:YAG laser operating at 1064 nm as the transmitter. The laser pulse is directed to the atmosphere using a 40 cm diameter scan mirror. The portion of the laser energy backscattered from aerosols and molecules is collected by a 40 cm diameter telescope and coupled via fiber optics into the Doppler receiver. Single photon counting APD's are used to detect the atmospheric backscattered signal. The principle element of the receiver is a dual bandpass tunable Fabry Perot etalon which analyzes the Doppler shift of the incoming laser signal using the double edge technique. The double edge technique uses two high resolution optical filters having bandpasses offset relative to one another such that the 'edge' of the first filter's transmission function crosses that of the second at the half power point. The outgoing laser frequency is located approximately at the crossover point. Due to the opposite going slopes of the edges, a Doppler shift in the atmospheric backscattered laser frequency produces a positive change in signal for one filter and a negative change in the second filter. Taking the ratio of the two edge channel signals yields a result which is directly proportional to the component of the wind along the line-of-sight of the laser. Measuring the radial wind in several directions provides sufficient information to determine the true wind speed and direction. The lidar has operated from our laboratory at Goddard since June, 1997. Wind profiles have been obtained to altitudes of 12 km with a vertical resolution of 330 in. Vector wind data are obtained by rotating the scan mirror to measure line-of-sight wind profiles for at least two azimuth angles at an elevation angle of 45 degrees. The precision of the data as determined from the standard deviation of multiple independent lidar profiles is in the range of 1 to 3 m/sec up to 10 km. Good agreement is obtained when the lidar data are compared with the upper air rawinsonde soundings taken at Dulles airport. Examples of the wind lidar data will be presented along with a description of the instrument and future developments.
Medium Modification of Vector Mesons
Chaden Djalali, Michael Paolone, Dennis Weygand, Michael H. Wood, Rakhsha Nasseripour
The theory of the strong interaction, Quantum Chromodynamics (QCD), has been remarkably successful in describing high-energy and short-distance-scale experiments involving quarks and gluons. However, applying QCD to low energy and large-distance scale experiments has been a major challenge. Various QCD-inspired models predict a partial restoration of chiral symmetry in nuclear matter with modifications of the properties of hadrons from their free-space values. Measurable changes such as a shift in mass and/or a change of width are predicted at normal nuclear density. Photoproduction of vector mesons off nuclei have been performed at different laboratories. The properties of the ?, ? and ? mesons are investigated either directly by measuring their mass spectra or indirectly through transparency ratios. The latest results regarding medium modifications of the vector mesons in the nuclear medium will be discussed.
Bond, V
Participants at a 2-day workshop on AIDS in Zambia concluded that women must openly discuss high-risk sexual behavior with their partners, if they are to protect themselves and their children. Entitled "Basic facts about AIDS," the workshop identified marital infidelity as the greatest source of risk. Last year, a study revealed that, on average, men and women in Zambia had 2-3 sexual partners outside marriage. Demographic and cultural factors also contribute to the spread of AIDS. Zambia's sexually active population is large, since people marry at a very young age. The traditional practice of "dry sex" -- intercourse that involves male penetration of a tight, dry vagina -- causes internal abrasions, thereby facilitating the transmission of HIV. Even traditional sex education undermines efforts to control the spread of AIDS, since "bamachimbusas" (traditional sex educators) counsel girls to be subservient to their husbands and "never say no." Boys receive no sex education at all. Meanwhile, Zambia faces an alarming HIV and AIDS trend, according to statistics collected by the Society for Women and AIDS (SWAAZ): in 1991, 12.5% of blood donors in Lusaka and 7.5% of donors nationwide were infected with HIV; infection among pregnant urban women ranged from 25-29%; 21% of malnourished children and 32% of children with tuberculosis are infected. Furthermore, it is estimated that by 1990, the AIDS epidemic had already orphaned 80,000 children. By the year 2000, it is believed that 1/2 million children will have lost at least one parent to the disease. PMID:12317434
A multidimensional histogram rain-flagging technique for SeaWinds on QuikSCAT
James N. Huddleston; Bryan W. Stiles
The SeaWinds scatterometer was developed by NASA JPL to measure the speed and direction of global ocean surface winds. SeaWinds was launched aboard the QuikSCAT spacecraft on June 19, 1999 and has continued to operate successfully since being turned on. Although the initial SeaWinds wind vector products were of excellent quality, they were occasionally degraded by the presence of rain.
Influence of Mean Wind Direction on Sea Surface Wave Development
S. Sethuraman
Momentum flux measurements made from an instrumented ocean buoy indicate that the surface drag coefficient C\\/sub d\\/ is strongly dependent on changes in mean wind direction. A change in mean wind direction is accompanied by a change in wave propagation direction and associated variations in wave steepness and stage of wave development. From simultaneous wind-stress and wave measurements, a critical
Balasundaram, Balabhaskar "Baski"
Wind Energy Leasing Handbook Wind Energy Leasing Handbook E-1033 Oklahoma Cooperative Extension? .................................................................................................................. 24 How has wind been used to generate power in the past?..................................................................................................................... 31 What do wind developers consider in locating wind energy projects
Understanding extreme winds in Iceland
NASA Astrophysics Data System (ADS)
Petersen, Gudrun Nina
Iceland is a fairly windy country, due to it's location adjacent the North Atlantic storm track. The orography of the island is rugged, mountains are steep and fjords and valleys narrow, and this impacts local winds. Thus, mountain wind phenomena such as low level jets, gap winds, down-slope wind storms, mountain waves and wind wakes are common. To increase our knowledge of the behaviour of wind in Iceland an extreme value analysis was conducted based on observations from 61 automatic weather stations, applying the Peak Over Threshold technique on maximum daily wind speed and maximum daily wind gust at each site. The time series included at least 10 years of data and the threshold was chosen as the 0.9 quantile of maximum mean wind speed/maximum wind gust at each location. Among the results is the larger impact the local orography has on the extreme wind gusts compared to the mean wind. With extreme value models in place, a few significant weather events were selected from recent years and the observed wind speeds compared to the models in order to evaluate how extreme the events were and how large area they impacted. Actually, in most of these events the observed wind speed only turned out to be extreme at a few stations, emphasising the local effects. However, in an event from December 2007, when the observed maximum wind speed exceeded 23 m/s in most of western Iceland, the event was estimated as rare at a number of weather stations. Clearly this gives indication for further studying this particular weather event. An automatic system has been set up, running once an hour, comparing observed wind measurements to the extreme value models and producing maps of the return periods for all sites. This system gives us the possibility to, on a daily basis, evaluate the extremeness of each situation and simultaneously increase our knowledge of extreme wind behaviour in Iceland. This work is a foundation for studying changes in extreme winds in Iceland.
Probabilistic Path Planning of Montgolfier Balloons in Strong, Uncertain Wind Fields
NASA Technical Reports Server (NTRS)
Wolf, Michael; Blackmore, James C.; Kuwata, Yoshiaki
Lighter-than-air vehicles such as hot-air balloons have been proposed for exploring Saturn s moon Titan, as well as other bodies with significant atmospheres. For these vehicles to navigate effectively, it is critical to incorporate the effects of surrounding wind fields, especially as these winds will likely be strong relative to the control authority of the vehicle. Predictive models of these wind fields are available, and previous research has considered problems of planning paths subject to these predicted forces. However, such previous work has considered the wind fields as known a priori, whereas in practical applications, the actual wind vector field is not known exactly and may deviate significantly from the wind velocities estimated by the model. A probabilistic 3D path-planning algorithm was developed for balloons to use uncertain wind models to generate time-efficient paths. The nominal goal of the algorithm is to determine what altitude and what horizontal actuation, if any is available on the vehicle, to use to reach a particular goal location in the least expected time, utilizing advantageous winds. The solution also enables one to quickly evaluate the expected time-to-goal from any other location and to avoid regions of large uncertainty. This method is designed for balloons in wind fields but may be generalized for any buoyant vehicle operating in a vector field. To prepare the planning problem, the uncertainty in the wind field is modeled. Then, the problem of reaching a particular goal location is formulated as a Markov decision process (MDP) using a discretized space approach. Solving the MDP provides a policy of what actuation option (how much buoyancy change and, if applicable, horizontal actuation) should be selected at any given location to minimize the expected time-to-goal. The results provide expected time-to-goal values from any given location on the globe in addition to the action policy. This stochastic approach can also provide insights not accessible by deterministic methods; for example, one can evaluate variability and risk associated with different scenarios, rather than only viewing the expected outcome.
Impact of Anthropogenic Environmental Alterations on Vector-Borne Diseases
Vora, Neil
The spread of infectious vector-borne diseases involves at least 3 organisms: a parasite, a vector, and a host. Alterations to the natural environment may change the context within which these entities interact, thus potentially affecting vector-borne disease epidemiology. In this review, examples are presented in which human-driven ecological changes may be contributing to the spread of vector-borne diseases. Such changes include deforestation, agriculture and animal husbandry, water control projects, urbanization, loss of biodiversity, introduction of alien species, and climate change. The global environment is currently being degraded at an alarming pace, potentially placing human populations at increasing risk for unnecessary and preventable outbreaks of vector-borne diseases. Further research is needed to improve our ability to predict and prevent emergence and reemergence of vector-borne diseases from environmental alterations. PMID:19099032
. . . . . . . . . . . . . . . . . . , . 67 APPENDIX G DISTRIBUTION OE LAKE CHARLES OBSERVED WIND DIPUECT1ON Wl', 'N TUE OUSL'RVL'D UOUSTON WIND DIR). CTION IS 1'ROill 'lklE EAST-NORTH- EAST, EAST, OR EAST- SOU'lklEAS'lL. . . . . . . . . . P aBa 72 APPENDIX II DETAII ED SOLUT10N... levels ro the results obtained b; rcg: i ssinf the Uouston low- levcl !&inde-aloft on the Houston surface wind. Althou?h d Leisure correlation coofficip!its show a definite urmr)er siinisiurs, they indicate that from &iB'/. to 77X (depending on season...
NASA Astrophysics Data System (ADS)
Owocki, Stan
A "stellar wind" is the continuous, supersonic outflow of matter from the surface layers of a star. Our sun has a solar wind, driven by the gas-pressure expansion of the hot (T > 106 K) solar corona. It can be studied through direct in situ measurement by interplanetary spacecraft; but analogous coronal winds in more distant solar-type stars are so tenuous and transparent that that they are difficult to detect directly. Many more luminous stars have winds that are dense enough to be opaque at certain wavelengths of the star's radiation, making it possible to study their wind outflows remotely through careful interpretation of the observed stellar spectra. Red giant stars show slow, dense winds that may be driven by the pressure from magnetohydrodyanmic waves. As stars with initial mass up to 8 M ? evolve toward the Asymptotic Giant Branch (AGB), a combination of stellar pulsations and radiative scattering off dust can culminate in "superwinds" that strip away the entire stellar envelope, leaving behind a hot white dwarf stellar core with less than the Chandrasekhar mass of � ?? 1. 4M ?. The winds of hot, luminous, massive stars are driven by line-scattering of stellar radiation, but such massive stars can also exhibit superwind episodes, either as Red Supergiants or Luminous Blue Variable stars. The combined wind and superwind mass loss can strip the star's hydrogen envelope, leaving behind a Wolf-Rayet star composed of the products of earlier nuclear burning via the CNO cycle. In addition to such direct effects on a star's own evolution, stellar winds can be a substantial source of mass, momentum, and energy to the interstellar medium, blowing open large cavities or "bubbles" in this ISM, seeding it with nuclear processed material, and even helping trigger the formation of new stars, and influencing their eventual fate as white dwarves or core-collapse supernovae. This chapter reviews the properties of such stellar winds, with an emphasis on the various dynamical driving processes and what they imply for key wind parameters like the wind flow speed and mass loss rate.
Keasler, J A
Vectorization is data parallelism (SIMD, SIMT, etc.) - extension of ISA enabling the same instruction to be performed on multiple data items simultaeously. Many/most CPUs support vectorization in some form. Vectorization is difficult to enable, but can yield large efficiency gains. Extra programmer effort is required because: (1) not all algorithms can be vectorized (regular algorithm structure and fine-grain parallelism must be used); (2) most CPUs have data alignment restrictions for load/store operations (obey or risk incorrect code); (3) special directives are often needed to enable vectorization; and (4) vector instructions are architecture-specific. Vectorization is the best way to optimize for power and performance due to reduced clock cycles. When data is organized properly, a vector load instruction (i.e. movaps) can replace 'normal' load instructions (i.e. movsd). Vector operations can potentially have a smaller footprint in the instruction cache when fewer instructions need to be executed. Hybrid index sets insulate users from architecture specific details. We have applied hybrid index sets to achieve optimal vectorization. We can extend this concept to handle other programming models.
Magnetic vector field tag and seal
Johnston, Roger G.; Garcia, Anthony R.
One or more magnets are placed in a container (preferably on objects inside the container) and the magnetic field strength and vector direction are measured with a magnetometer from at least one location near the container to provide the container with a magnetic vector field tag and seal. The location(s) of the magnetometer relative to the container are also noted. If the position of any magnet inside the container changes, then the measured vector fields at the these locations also change, indicating that the tag has been removed, the seal has broken, and therefore that the container and objects inside may have been tampered with. A hollow wheel with magnets inside may also provide a similar magnetic vector field tag and seal. As the wheel turns, the magnets tumble randomly inside, removing the tag and breaking the seal.
Network Power Flow Control of Variable Speed Wind Turbine
D. Aouzellag; K. Ghedamsi; E. M. Berkouk
In this paper, a grid connected wind power generation scheme using a doubly fed induction generator (DFIG) is studied. The objectives of this paper are: - Modelling and simulating of a DFIG operating in two quadrants (torque-speed plane). - Analysing employs a stator flux vector control algorithm used with a space vector modulated matrix converter controlling rotor current. - Enabling
Introduction Strict vector coloring Vector coloring Quantum coloring Further work Hedetniemi conjecture for strict vector
Severini, Simone
Introduction Strict vector coloring Vector coloring Quantum coloring Further work Hedetniemi conjecture for strict vector chromatic number Robert S�mal (joint with C.Godsil, D.Roberson, S vector coloring Vector coloring Quantum coloring Further work Outline 1 Introduction 2 Strict vector
Understanding Inertial and Frequency Response of Wind Power Plants: Preprint
Muljadi, E.; Gevorgian, V.; Singh, M.; Santoso, S.
The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).
Wind speed PDF classification using Dirichlet mixtures Rudy CALIF1
Paris-Sud XI, Universit� de
Wind speed PDF classification using Dirichlet mixtures Rudy CALIF1 , Richard EMILION2 , Ted'Orl�ans), UMR CNRS 6628 Universit� d'Orl�ans, France. Abstract: Wind energy production is very sensitive to instantaneous wind speed fluctuations. Thus rapid variation of wind speed due to changes in the local
Vector Quantization With Emergent Codebook Structure
NASA Technical Reports Server (NTRS)
Ahalt, Stanley C.; Krishnamurthy, Ashok
Proposed scheme under development for transmission of vector-quantized digital video images, vector quantizer codebook updated to adapt quantizer to changing signal statistics. Intended to be realized with electronic neural network. Codebook, which consists of patterns constituting video images, will undergo training during operation and scheme will develop codebooks ordered during training. System enables coding more compact, more immune to noise, and supports variable rate compression.
National assessment of shoreline change: a GIS compilation of vector shorelines and associated shoreline change data for the north coast of Alaska, U.S.-Canadian border to Icy Cape
Gibbs, Ann E.; Karen A. Ohman; Richmond, Bruce M.
There is no widely accepted standard for analyzing shoreline change. Existing shoreline data measurements and rate calculation methods vary from study to study and prevent combining results into state-wide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method of measuring changes in shoreline position that is consistent from coast to coast. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner. A detailed report on shoreline change for the north coast of Alaska that contains a discussion of the data presented here is available and cited in section, "Geospatial Data."
A `low-level' explanation for the recent large warming trend over the western Antarctic Peninsula involving blocked winds and changes in zonal circulation
NASA Astrophysics Data System (ADS)
Orr, A.; Cresswell, D.; Marshall, G. J.; Hunt, J. C. R.; Sommeria, J.; Wang, C. G.; Light, M.
We demonstrate a mechanism whereby the impact of stronger circumpolar westerly winds on the mountains of the Antarctic Peninsula contributes significantly to the enhanced warming trend observed over its western side in the last 50 years. Numerical and laboratory meteorological modelling demonstrate how, when westerly winds impinge on this side, warm air below the height (1.5-2.0 km) of the Peninsula is advected in a southerly direction. The strength of the annual mean westerly winds has increased by about 15-20% since the 1960s, while the modelling results indicate that contemporaneously the air advected to its western side originates from an increasingly northerly (and warmer) location. This gives rise to increased northerlies and a greater transport of warm air into this region. Consequently there is a reduction in the sea-ice extent, further amplifying the local warming. This `low-level', orographic mechanism for the local climate trend is supported by observational evidence.
Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region
Background Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic animal populations. Lyme disease (LD) is the most prevalent arthropod borne disease in the US and Europe. The bacterium Borrelia burgdorferi causes LD and it is transmitted to humans and other mammalian hosts through the bite of infected Ixodes ticks. LD risk maps in the transboundary region between the U.S. and Mexico are lacking. Moreover, none of the published studies that evaluated the effect of climate change in the spatial and temporal distribution of I. scapularis have focused on this region. Methods The area of study included Texas and a portion of northeast Mexico. This area is referred herein as the Texas-Mexico transboundary region. Tick samples were obtained from various vertebrate hosts in the region under study. Ticks identified as I. scapularis were processed to obtain DNA and to determine if they were infected with B. burgdorferi using PCR. A maximum entropy approach (MAXENT) was used to forecast the present and future (2050) distribution of B. burgdorferi-infected I. scapularis in the Texas-Mexico transboundary region by correlating geographic data with climatic variables. Results Of the 1235 tick samples collected, 109 were identified as I. scapularis. Infection with B. burgdorferi was detected in 45% of the I. scapularis ticks collected. The model presented here indicates a wide distribution for I. scapularis, with higher probability of occurrence along the Gulf of Mexico coast. Results of the modeling approach applied predict that habitat suitable for the distribution of I. scapularis in the Texas-Mexico transboundary region will remain relatively stable until 2050. Conclusions The Texas-Mexico transboundary region appears to be part of a continuum in the pathogenic landscape of LD. Forecasting based on climate trends provides a tool to adapt strategies in the near future to mitigate the impact of LD related to its distribution and risk for transmission to human populations in the Mexico-US transboundary region. PMID:24766735
Vector curvaton without instabilities
NASA Astrophysics Data System (ADS)
Dimopoulos, Konstantinos; Kar?iauskas, Mindaugas; Wagstaff, Jacques M.
A vector curvaton model with a Maxwell kinetic term and varying kinetic function and mass during inflation is studied. It is shown that, if light until the end of inflation, the vector field can generate statistical anisotropy in the curvature perturbation spectrum and bispectrum, with the latter being predominantly anisotropic. If by the end of inflation the vector field becomes heavy, then particle production is isotropic and the vector curvaton can alone generate the curvature perturbation. The model does not suffer from instabilities such as ghosts and is the only concrete model, to date, which can produce the curvature perturbation without direct involvement of fundamental scalar fields.
NSDL National Science Digital Library
Formed in 1968, the Society for Vector Ecology (SOVE) is dedicated to studying "all aspects of the biology, ecology, and control of arthropod vectors and the interrelationships between the vectors and the disease agents they transmit." Comprised of researchers and operational and extension personnel around the globe, SOVE tracks and studies the biological organisms that transmit diseases. The SOVE Website contains information related to the Society (e.g., mission, history), its publications (journal, newsletter -- both .pdf format), and professional opportunities (conferences, employment). Several dozen links to additional vector ecology resources are provided.
Advanced algorithms for QuikScat and SeaWinds\\/AMSR
Frank J. Wentz; Deborah K. Smith; Carl A. Mears; Chelle L. Gentemann
QuikScat is providing scientists and weather forecasters with an unprecedented view of ocean winds at a 25-km resolution. With a typical accuracy of 1 m\\/s in speed and 15� in direction, the retrieved wind vectors are being used for a number of important oceanographic and air\\/sea interaction studies. We present work on a QuikScat wind-vector retrieval algorithm that contains a
The Effects of Solar Wind Dynamic Pressure on the Coupling of Energy between the Solar Wind and Magnetosphere
Elizabeth Mitchell; Ramon Lopez
Space physics seeks to understand the solar wind conditions which determine the interactions between the magnetosphere to the solar wind. In this pursuit, we are considering the effects of the changes in the solar wind dynamic pressure on the coupling between the solar wind electric field and the ring current injection rate (RCIR). The RCIR indicates the scale of the
Sodar-derived structural functions of the wind velocity field
L. G. Shamanaeva
The structural functions of the wind velocity field reconstructed from the vertical profiles of the wind velocity vector measured with the Zvuk-2 three-channel monostatic Doppler sodar (1700 Hz) and a commercial minisodar of the Atmospheric Systems Corporation (4900 Hz) are presented in the report. The Doppler sodars allow long-term series of instantaneous values of the three wind velocity components in
NASA Astrophysics Data System (ADS)
Xia, Xiang-Gen; Suter, Bruce W.; Huang, Ying
Scalar-valued Malvar wavelets have been used to eliminate the blocking effects in scalar transform coding. In this paper, we introduce vector-valued Malvar wavelets for vector-valued signals. While constructing window vectors, we present a connection between vector-valued Malvar wavelets and vector Lemarie-Meyer band-limited wavelets. Similar to scalar-valued Malvar wavelets, vector-valued Malvar wavelets have applications in eliminating the blocking effects in vector transform coding.
Three-dimensional elastic lidar winds
Buttler, W.T.
Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three- dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain following winds in the Rio Grande valley.
Progress in malaria vector control*
Pant, C. P.; Rishikesh, N.; Bang, Y. H.; Smith, A.
Malaria control, except in tropical Africa, will probably continue to be based to a large extent on the use of insecticides for many years. However, the development of resistance to insecticides in the vectors has caused serious difficulties and it is necessary to change the strategy of insecticide use to maximize their efficacy. A thorough knowledge of the ecology and behaviour of each vector species is required before the control strategy can be adapted to different epidemiological situations. The behavioural differences between sibling species have been recognized for several years, but study of this problem has recently been simplified by improved means of identification that involve chromosomal banding patterns and electrophoretic analysis. Behavioural differences have also been associated with certain chromosomal rearrangements. New records of insecticide resistance among anophelines continue to appear and the impact of this on antimalaria operations has been seriously felt in Central America (multi-resistance in Anopheles albimanus), Turkey (A. sacharovi), India and several Asian countries (A. culicifacies and A. stephensi), and some other countries. Work continues on the screening and testing of newer insecticides that can be used as alternatives, but DDT, malathion, temephos, fenitrothion, and propoxur continue to be used as the main insecticides in many malaria control projects. The search for simpler and innovative approaches to insecticide application also continues. Biological control of vectors is receiving increased attention, as it could become an important component of integrated vector control strategies, and most progress has been made with the spore-forming bacterium, serotype H-14 of Bacillus thuringiensis. Larvivorous fish such as Gambusia spp. and Poecilia spp. continue to be used in some programmes. Application of environmental management measures, such as source reduction, source elimination, flushing of drainage and irrigation channels, and intermittent irrigation have been re-examined and currently a great deal of interest is being shown in these approaches. There has been limited interest in the genetic control of mosquitos and the phenomenon of refractoriness in some strains of the disease vectors, with the idea of replacing the vector species with the refractory strain. More research is needed before this approach can become a practical tool. It is apparent that in future a more integrated approach will have to be used for vector control within the context of antimalaria programmes. Training of staff, research, and cooperation at all levels will be an essential requirement for this approach. PMID:6976842
Denoising 2-D Vector Fields by Vector Wavelet Thresholding
Westenberg, Michel A.
Denoising 2-D Vector Fields by Vector Wavelet Thresholding Michel A. Westenberg and Thomas Ertl for denoising 2-D vector fields that are corrupted by additive noise. The method is based on the vector wavelet introduce modifications to scalar wavelet coefficient thresholding for dealing with vector
Construction of Solar-Wind-Like Magnetic Fields
NASA Technical Reports Server (NTRS)
Roberts, Dana Aaron
Fluctuations in the solar wind fields tend to not only have velocities and magnetic fields correlated in the sense consistent with Alfven waves traveling from the Sun, but they also have the magnitude of the magnetic field remarkably constant despite their being broadband. This paper provides, for the first time, a method for constructing fields with nearly constant magnetic field, zero divergence, and with any specified power spectrum for the fluctuations of the components of the field. Every wave vector, k, is associated with two polarizations the relative phases of these can be chosen to minimize the variance of the field magnitude while retaining the\\random character of the fields. The method is applied to a case with one spatial coordinate that demonstrates good agreement with observed time series and power spectra of the magnetic field in the solar wind, as well as with the distribution of the angles of rapid changes (discontinuities), thus showing a deep connection between two seemingly unrelated issues. It is suggested that using this construction will lead to more realistic simulations of solar wind turbulence and of the propagation of energetic particles.
A corrected hybrid approach for wind speed prediction in Hexi Corridor of China
Zhenhai Guo; Jing Zhao; Wenyu Zhang; Jianzhou Wang
Wind energy has been well recognized as a renewable resource in electricity generation, which is environmentally friendly, socially beneficial and economically competitive. For proper and efficient evaluation of wind energy, a hybrid Seasonal Auto-Regression Integrated Moving Average and Least Square Support Vector Machine (SARIMA�LSSVM) model is significantly developed to predict the mean monthly wind speed in Hexi Corridor. The design
Lapped Orthogonal Vector Quantization
Henrique S. Malvar; Gary J. Sullivan; Gregory W. Wornell
The blocking artifacts that arise in the use of traditional vector quantization (VQ) schemes can, in general, be virtually eliminated via an efficient lapped VQ strategy. With lapped VQ, blocks are obtained from the source in an overlapped manner, and reconstructed via superposition of overlapped codevectors. The new scheme, which we term lapped orthogonal vector quantization (LOVQ), requires no increase
Exploring acceleration through vectors
NSDL National Science Digital Library
This in class worksheet is designed to get students to think about and manipulate different accelerations in their head. Students work together with written descriptions of velocity and acceleration and draw the vectors in part one, and then turn that around in part two where they write descriptions of a car's motion based on the vector pictures they are given.
Insect vector transmission assays.
Bosco, Domenico; Tedeschi, Rosemarie
Phytoplasmas are transmitted in a persistent propagative manner by phloem-feeding vectors belonging to the order Hemiptera, suborder Homoptera. Following acquisition from the infected source plant, there is a latent period before the vector can transmit, so transmission assays consist of three basic steps: acquisition, latency, and inoculation. More than 90 vector species (plant-, leafhoppers, and psyllids) have been discovered so far but many others are still undiscovered, and their role in spreading economically important crop diseases is neglected. Therefore, screening for vectors is an essential step in developing rational control strategies targeted against the actual vectors for phytoplasma-associated diseases. The mere detection of a phytoplasma in an insect does not imply that the insect is a vector; a transmission assay is required to provide conclusive evidence. Transmission experiments can be carried out using insects from phytoplasma-free laboratory colonies or field-collections. Moreover, transmission assays can be performed by feeding vectors on an artificial diet through Parafilm(�), after which phytoplasmas can be detected in the sucrose feeding medium by PCR. Transmission trials involve the use of different techniques according to the biology of the different vector species; planthoppers, leafhoppers, and psyllids. PMID:22987407
Bernhard Sch�lkopf; Alex J. Smola; Robert C. Williamson; Peter L. Bartlett
We propose a new class of support vector algorithms for regression and classification. In these algorithms, a parameter ? lets one effectively control the number of support vectors. While this can be useful in its own right, the parameterization has the additional benefit of enabling us to eliminate one of the other free parameters of the algorithm: the accuracy parameter
Doppler Lidar for Wind Measurements on Venus
NASA Technical Reports Server (NTRS)
Singh, Upendra N.; Emmitt, George D.; Yu, Jirong; Kavaya, Michael J.
NASA Langley Research Center has a long history of developing 2-micron laser transmitter for wind sensing. With support from NASA Laser Risk Reduction Program (LRRP) and Instrument Incubator Program (IIP), NASA Langley Research Center has developed a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement. The transmitter portion of the transceiver employs the high-pulse-energy, Ho:Tm:LuLiF, partially conductively cooled laser technology developed at NASA Langley. The transceiver is capable of 250 mJ pulses at 10 Hz. It is very similar to the technology envisioned for coherent Doppler lidar wind measurements from Earth and Mars orbit. The transceiver is coupled to the large optics and data acquisition system in the NASA Langley VALIDAR mobile trailer. The large optics consists of a 15-cm off-axis beam expanding telescope, and a full-hemispheric scanner. Vertical and horizontal vector winds are measured, as well as relative backscatter. The data acquisition system employs frequency domain velocity estimation and pulse accumulation. It permits real-time display of the processed winds and archival of all data. This lidar system was recently deployed at Howard University facility in Beltsville, Mary-land, along with other wind lidar systems. Coherent Doppler wind lidar ground-based wind measurements and comparisons with other sensors will be presented. A simulation and data product for wind measurement at Venus will be presented.
Vector Piezoresponse Force Microscopy
Kalinin, Sergei V [ORNL; Rodriguez, Brian J [ORNL; Jesse, Stephen [ORNL; Shin, Junsoo [ORNL; Baddorf, Arthur P [ORNL; Gupta, P. [Lehigh University, Bethlehem, PA; Jain, H. [Lehigh University, Bethlehem, PA; Williams, D. B. [Lehigh University, Bethlehem, PA; Gruverman, A. [North Carolina State University
A novel approach for nanoscale imaging and characterization of the orientation dependence of electromechanical properties - vector piezoresponse force microscopy (Vector PFM) - is described. The relationship between local electromechanical response, polarization, piezoelectric constants, and crystallographic orientation is analyzed in detail. The image formation mechanism in vector PFM is discussed. Conditions for complete three-dimensional (3D) reconstruction of the electromechanical response vector and evaluation of the piezoelectric constants from PFM data are set forth. The developed approach can be applied to crystallographic orientation imaging in piezoelectric materials with a spatial resolution below 10 nm. Several approaches for data representation in 2D-PFM and 3D-PFM are presented. The potential of vector PFM for molecular orientation imaging in macroscopically disordered piezoelectric polymers and biological systems is discussed.
Study and simulation of space vector PWM control of double-star induction motors
D. Hadiouche; H. Razik; A. Rezzoug
This paper deals with a comparison between different structures of double-star induction motors (DSIMs), controlled by space vector PWM. The modelling of the DSIM is made using an arbitrary shift angle between the two three-phase windings. A new transformation matrix is proposed to develop a suitable dynamic model and to elaborate the space vector PWM control strategy for different values
Wiser, Ryan H.; Bolinger, Mark; Barbose, G.; Mills, A.; Rosa, A.; Porter, K.; Fink, S.; Tegen, S.; Musial, W.; Oteri, F.; Heimiller, D.; Rberts, B.; Belyeu, K.; Stimmel, R.
The U.S. wind industry experienced a banner year in 2008, again surpassing even optimistic growth projections from years past. At the same time, the last year has been one of upheaval, with the global financial crisis impacting near-term growth prospects for the wind industry, and with federal policy changes enacted to push the industry towards continued aggressive expansion. This rapid pace of development has made it difficult to keep up with trends in the marketplace. Yet, the need for timely, objective information on the industry and its progress has never been greater. This report - the third of an ongoing annual series - attempts to meet this need by providing a detailed overview of developments and trends in the U.S. wind power market, with a particular focus on 2008. As with previous editions, this report begins with an overview of key wind power installation-related trends: trends in wind capacity growth in the U.S., how that growth compares to other countries and generation sources, the amount and percentage of wind in individual states and serving specific utilities, and the quantity of proposed wind capacity in various interconnection queues in the United States. Next, the report covers an array of wind industry trends, including developments in turbine manufacturer market share, manufacturing and supply-chain investments, wind turbine and wind project size, project financing developments, and trends among wind power developers, project owners, and power purchasers. The report then turns to a discussion of wind project price, cost, and performance trends. In so doing, it reviews the price of wind power in the United States, and how those prices compare to the cost of fossil-fueled generation, as represented by wholesale power prices. It also describes trends in installed wind project costs, wind turbine transaction prices, project performance, and operations and maintenance expenses. Next, the report examines other policy and market factors impacting the domestic wind power market, including federal and state policy drivers, transmission issues, and grid integration. Finally, the report concludes with a preview of possible near- to medium-term market developments. This version of the Annual Report updates data presented in the previous editions, while highlighting key trends and important new developments from 2008. New to this edition is an executive summary of the report and an expanded final section on near- to medium-term market development. The report concentrates on larger-scale wind applications, defined here as individual turbines or projects that exceed 50 kW in size. The U.S. wind power sector is multifaceted, however, and also includes smaller, customer-sited wind turbines used to power the needs of residences, farms, and businesses. Data on these applications are not the focus of this report, though a brief discussion on Distributed Wind Power is provided on page 4. Much of the data included in this report were compiled by Berkeley Lab, and come from a variety of sources, including the American Wind Energy Association (AWEA), the Energy Information Administration (EIA), and the Federal Energy Regulatory Commission (FERC). The Appendix provides a summary of the many data sources used in the report. Data on 2008 wind capacity additions in the United States are based on information provided by AWEA; some minor adjustments to those data may be expected. In other cases, the data shown here represent only a sample of actual wind projects installed in the United States; furthermore, the data vary in quality. As such, emphasis should be placed on overall trends, rather than on individual data points. Finally, each section of this document focuses on historical market information, with an emphasis on 2008; with the exception of the final section, the report does not seek to forecast future trends.
Is a significant socio-economic structural change a pre-requisite for "inital" fertility decline in the LDCs? Evidence from Thailand based on a multivariate cointegration / vector error correction modelling approach.
Masih, A M; Masih, R
This study is a first attempt at placing the analysis of fertility in a temporal dynamic framework in the case of a developing Asian economy like Thailand by binding the relationship between fertility and its determinants within a cointegrated system. In this respect, the focus of this paper is to shed light on whether a significant socioeconomic structural transition is a requirement to ensure initial fertility decline. The analysis is based on the application of the dynamic time series techniques: cointegration, vector-error correction modeling, variance decompositions, and impulse response functions. The findings tend to suggest that in the complex dynamic interactions, the importance of the conventional structural hypothesis as a significant factor in reducing fertility in the longer term cannot be denied. However, in the short to longer term, the results, although not fully supportive of any particular hypothesis, appear to be broadly consistent with the hypothesis highlighting the critical role of ideational or diffusion forces along the demographic factors in ensuring initial fertility decline than with the structural hypothesis emphasizing a significant socioeconomic structural change as a prerequisite for initial decline in fertility. PMID:12295836
77 FR 29633 - Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC...
Federal Register 2010, 2011, 2012, 2013, 2014
...EL12-68-000] Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC, Alta Wind XIII...385.207, Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC, Alta Wind...
2008 Wind Technologies Market Report
Wiser, R.; Bolinger, M.
The U.S. wind industry experienced a banner year in 2008, once again surpassing even optimistic growth projections from years past. At the same time, the past year has been one of upheaval, with the global financial crisis impacting near-term growth prospects for the wind industry, and with significant federal policy changes enacted to push the industry toward continued aggressive expansion. This report examines key trends.
ESL-TR-12-07-01 STATEWIDE AIR EMISSIONS CALCULATIONS FROM WIND AND OTHER RENEWABLES SUMMARY REPORT A Report to the Texas Commission on Environmental Quality For the Period September 2011 � July 2012 Jeff Haberl, Ph.D., P.E... 2003 2004 2005 2006 2007 2008 2009 2010 2011 E l e c t r i c i t y G e n e r a t e d i n M W h Year Annual Electricity Generated in Texas by Renewable Sources Biomass Hydro Landfill gas Solar Wind Figure 1-5: Electricity Generation...
Wind tunnel investigation on wind turbine wakes and wind farms
NASA Astrophysics Data System (ADS)
Iungo, G. V.; Co�ff�, J.; Port�-Agel, F.
The interaction between atmospheric boundary layer and wind farms leads to flow modifications, which need to be deeply characterized in order to relate them to wind farm performance. The wake flow produced from a wind farm is the result of a strong interaction between multiple turbine wakes, so that the wind farm configuration turns out to be one of the dominant features to enhance power production. For the present work a wind tunnel investigation was carried out with hot-wire anemometry and velocity measurements performed with multi-hole pressure probes. The tested wind farms consist of miniature three-bladed wind turbine models. Preliminarily, the wake flow generated from a single wind turbine is surveyed, which is characterized by a strong velocity defect lying in proximity of the wind turbine hub height. The wake gradually recovers by moving downstream; the characteristics of the incoming boundary layer and wind turbulence intensity can strongly affect the wake recovery, and thus performance of following wind turbines. An increased turbulence level is typically detected downstream of each wind turbine for heights comparable to the wind turbine blade top-tip. These wake flow fluctuations produce increased fatigue loads on the following wind turbines within a wind farm, which could represent a significant hazard for real wind turbines. Dynamics of vorticity structures present in wind turbine wakes are also investigated; particular attention is paid to the downstream evolution of the tip helicoidal vortices and to oscillations of the hub vortex. The effect of wind farm layout on power production is deeply investigated. Particular emphasis is placed on studying how the flow adjusts as it moves inside the wind farm and can affect the power production. Aligned and staggered wind farm configurations are analysed, also with varying separation distances in the streamwise and spanwise directions. The present experimental results are being used to test and guide the development of improved parameterizations of wind turbines in high-resolution numerical models, such as large-eddy simulations (LES).
The Change in Cosmic Ray Intensity Variation with the Solar Wind Velocity (Using GRAPES3 muon narrow angle telescopes and Kiel neutron monitor)
H. Kojima; Y. Hayashi; K. Hayashi
GRAPES-3 experiment is situated at Ooty in South India 76.7 East 11.4 North. Effective observation area of our muon telescopes is 560 m2. They are the largest detector in the world of its kind. There were several reports that increase of the solar wind velocity suppresses the intensity of cosmic rays. But there are few which studied qualitatively. We have
Kristen T. Bradford; Richard L. Carpenter; Brent L. Shaw
Wind ramp events�extreme and rapid changes in wind power output due to abrupt changes in wind speed�are a growing concern for the wind energy industry; therefore, precise forecasting of these phenomena is crucial to the advancement of wind power in the United States. Weather Decision Technologies, Inc., (WDT) is partnering with NanoWeather, Inc., to create a wind forecasting system, called
Numerical investigation of wind turbine and wind farm aerodynamics
NASA Astrophysics Data System (ADS)
Selvaraj, Suganthi
A numerical method based on the solution of Reynolds Averaged Navier Stokes equations and actuator disk representation of turbine rotor is developed and implemented in the OpenFOAM software suite for aerodynamic analysis of horizontal axis wind turbines (HAWT). The method and the implementation are validated against the 1-D momentum theory, the blade element momentum theory and against experimental data. The model is used for analyzing aerodynamics of a novel dual rotor wind turbine concept and wind farms. Horizontal axis wind turbines suffer from aerodynamic inefficiencies in the blade root region (near the hub) due to several non-aerodynamic constraints (e.g., manufacturing, transportation, cost, etc.). A new dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating these losses. A DRWT is designed using an existing turbine rotor for the main rotor (Risoe turbine and NREL 5 MW turbine), while the secondary rotor is designed using a high lift to drag ratio airfoil (the DU 96 airfoil from TU Delft). The numerical aerodynamic analysis method developed as a part of this thesis is used to optimize the design. The new DRWT design gives an improvement of about 7% in aerodynamic efficiency over the single rotor turbine. Wind turbines are typically deployed in clusters called wind farms. HAWTs also suffer from aerodynamic losses in a wind farm due to interactions with wind turbine wakes. An interesting mesoscale meteorological phenomenon called "surface flow convergence" believed to be caused by wind turbine arrays is investigated using the numerical method developed here. This phenomenon is believed to be caused by the pressure gradient set up by wind turbines operating in close proximity in a farm. A conceptual/hypothetical wind farm simulation validates the hypothesis that a pressure gradient is setup in wind farms due to turbines and that it can cause flow veering of the order of 10 degrees. Simulations of a real wind farm (Story County) are also conducted which give qualitatively correct flow direction change, however quantitative agreement with data is only moderately acceptable.
NSDL National Science Digital Library
K-12 Outreach Office,
Students are challenged to design and build wind chimes using their knowledge of physics and sound waves, and under given constraints such as weight, cost and number of musical notes it must generate. They make mathematical computations to determine the pipe lengths.
NSDL National Science Digital Library
This module provides a basic understanding of why gap winds occur, their typical structures, and how gap wind strength and extent are controlled by larger-scale, or synoptic, conditions. You will learn about a number of important gap flows in coastal regions around the world, with special attention given to comprehensively documented gap wind cases in the Strait of Juan de Fuca and the Columbia River Gorge. Basic techniques for evaluating and predicting gap flows are presented. The module reviews the capabilities and limitations of the current generation of mesoscale models in producing realistic gap winds. By the end of this module, you should have sufficient background to diagnose and forecast gap flows around the world, and to use this knowledge to understand their implications for operational decisions. Other features in this module include a concise summary for quick reference and a final exam to test your knowledge. Like other modules in the Mesoscale Meteorology Primer, this module comes with audio narration, rich graphics, and a companion print version.
Maximum power tracking control scheme for wind generator systems
Mena, Hugo Eduardo
solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier...
Maximum power tracking control scheme for wind generator systems
Mena Lopez, Hugo Eduardo
solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier...
Deceleration of the solar wind upstream from the earth's bow shock and the origin of diffuse upstream ions
NASA Technical Reports Server (NTRS)
Bame, S. J.; Asbridge, J. R.; Feldman, W. C.; Gosling, J. T.; Paschmann, G.; Skopke, N.
Observations with the Los Alamos Scientific Laboratory/Max-Planck-Institut crossed-fan solar wind ion experiment on ISEE I reveal that the solar wind is decelerated and deflected away from the direction of the earth's bow shock as it enters that portion of the upstream region populated by diffuse bow shock ions and long-period (10-60 s) waves. Typically, the average directed velocity vector changes by 7-10 km/s as it enters the wave region. At times, average speed changes as large as 25-40 km/s are observed. Superposed upon these changes in average flow speed are large amplitude (+ or - 15) fluctuations in flow speed associated with the waves themselves. The observations suggest that the solar wind deceleration is the result of momentum transfer from reflected bow shock ions to the wind via the long-period waves as the reflected ion beams go unstable. The broad angular distributions of the diffuse ions thus appear to be produced as a consequence of the disruption of reflected ion beams.
Carrigan, Charles R. (Tracy, CA)
A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.
NASA Technical Reports Server (NTRS)
Wang, Li-Jun; Bacon, A. M.; Zhao, H.-Z.; Thomas, J. E.
In the optical measurement of the Bloch vector components describing a system of N two-level atoms, the quantum fluctuations in these components are coupled into the measuring optical field. This paper develops the quantum theory of optical measurement of Bloch vector projection noise. The preparation and probing of coherence in an effective two-level system consisting of the two ground states in an atomic three-level lambda-scheme are analyzed.
WindSat Polarimetric Microwave Radiometer: Advanced Sensor Products and Risk Reduction
NASA Astrophysics Data System (ADS)
Gaiser, P. W.; Bettenhausen, M. H.; Li, L.; Adams, I.
WindSat, a satellite-based multi-frequency polarimetric microwave radiometer developed by the Naval Research Laboratory for the U.S. Navy and the NPOESS Integrated Program Office (IPO), has collected more than five years of fully-polarimetric microwave measurements from space since its launch in 2003. The primary WindSat mission was to demonstrate the capability retrieve the ocean surface wind vector from a space-based microwave radiometer. The WindSat data are now used to produce near-real-time products for the ocean surface wind vector, sea surface temperature and atmospheric columnar water vapor and cloud liquid water over the ocean at the U.S. Navy's Fleet Numerical Meteorological and Oceanographic Center. WindSat products are also being assimilated into numerical weather models with positive results. To further exploit the unique WindSat data set, significant effort has gone into improving the spatial resolution of the WindSat ocean products. Higher spatial resolution not only better resolves the wind field, but also improves high wind speed retrievals because of the smaller spatial scales of higher winds. Furthermore, reduced spatial resolution allows for retrievals closer to coastlines. The current WindSat ground data processing software produces retrievals at three spatial resolutions (pixel sizes of 50x71 km; 35x53 km; and 25x35 km). The WindSat mission, sensor, and data products serve as risk reduction for the NPOESS Microwave Imager Sounder (MIS). In addition to demonstrating the ocean surface vector wind measurement capability, WindSat has been used to study MIS performance for other parameters such as soil moisture. The WindSat data set is also useful for understanding the radio frequency interference (RFI) environment in which MIS must operate. WindSat data are being used in MIS sensitivity and performance analyses. Lastly, the design of MIS will rely heavily on the heritage of the WindSat sensor.
Wind Technologies & Evolving Opportunities (Presentation)
Robichaud, R.
This presentation covers opportunities for wind technology; wind energy market trends; an overview of the National Wind Technology Center near Boulder, Colorado; wind energy price and cost trends; wind turbine technology improvements; and wind resource characterization improvements.
Sensitivity of the wind stress and storm surges to surface drag
Vries, Hans de
Sensitivity of the wind stress and storm surges to surface drag changes Niels Zweers KNMI - Weather concept � Methodology � HIRLAM � WAQUA � Results � Conclusion Sensitivity of the wind stress and storm and `moderate' wind speeds Sensitivity of the wind stress and storm surges to surface drag changes Delft, 27
Solar wind and magnetosphere interactions
NASA Technical Reports Server (NTRS)
Russell, C. T.; Allen, J. H.; Cauffman, D. P.; Feynman, J.; Greenstadt, E. W.; Holzer, R. E.; Kaye, S. M.; Slavin, J. A.; Manka, R. H.; Rostoker, G.
The relationship between the magnetosphere and the solar wind is addressed. It is noted that this interface determines how much of the solar plasma and field energy is transferred to the Earth's environment, and that this coupling not only varies in time, responding to major solar disturbances, but also to small changes in solar wind conditions and interplanetary field directions. It is recommended that the conditions of the solar wind and interplanetary medium be continuously monitored, as well as the state of the magnetosphere. Other recommendations include further study of the geomagnetic tail, tests of Pc 3,4 magnetic pulsations as diagnostics of the solar wind, and tests of kilometric radiation as a remote monitor of the auroral electrojet.
NASA Astrophysics Data System (ADS)
Boffin, Henri M. J.
I review the process of mass transfer in a binary system through a stellar wind, with an emphasis on systems containing a red giant. I show how wind accretion in a binary system is different from the usually assumed Bondi-Hoyle approximation, first as far as the flow's structure is concerned, but most importantly, also for the mass accretion and specific angular momentum loss. This has important implications on the evolution of the orbital parameters. I also discuss the impact of wind accretion, on the chemical pollution and change in spin of the accreting star. The last section deals with observations and covers systems that most likely went through wind mass transfer: barium and related stars, symbiotic stars and central stars of planetary nebulae (CSPN). The most recent observations of cool CSPN progenitors of barium stars, as well as of carbon-rich post-common envelope systems, are providing unique constraints on the mass transfer processes.
Faraday's law via the magnetic vector potential
Dragan V Red�i?
Faraday's law for a filamentary circuit which is moving at relativistic velocities and also changing its shape as it moves is derived via the magnetic vector potential. The derivation is simpler than the usual one, based on the Hertz�Helmholtz identity.
Hierarchal scalar and vector tetrahedra
J. P. Webb; B. Forgahani
A novel set of scalar and vector tetrahedral finite elements are presented. The elements are hierarchical, allowing mixing of polynomial orders. Scalar orders up to three and vector orders up to two are defined. The vector elements impose tangential continuity on the field but not normal continuity, making them suitable for representing the vector electric or magnetic field. The scalar
Remote Sensing of the 3D Wind and Turbulence Field by Coherent Doppler Lidars for Wind Power Applications
NASA Astrophysics Data System (ADS)
Sj�holm, M.; Courtney, M. S.; Enevoldsen, K. M.; Lindel�w, P.; Mann, J.; Mikkelsen, T.
For several decades Ris� DTU has been involved in wind power meteorology and during the last half- decade the performance of commercially available coherent wind Doppler Lidars have been extensively studied at the test station for large wind turbines, H�vs�re, in Western Jutland, Denmark. One aspect of wind Lidars, in contrast to many in-situ wind-monitoring instruments, is that they are not truly point-monitoring devices but the wind speed measured is rather a weighted average of the line-of-sight velocity component over an extended spatial volume. The width of the weighting function along the beam is for pulsed systems mainly determined by the laser pulse length together with the sampling duration for a single Doppler spectrum, whereas for continuous-wave systems the focal depth of the laser beam determines the weighting width. Here, some recent results regarding the effect of this spatial volume averaging on turbulence measurements are presented. One common approach to obtain the whole wind vector is to perform a conical scan of the Lidar laser beam, which under the horizontal homogeneity assumption allows for the wind vector to be extracted. The wind vector measured is thus, in some sense, averaged over a substantial lateral area and time. However, temporal as well as spatial resolution of the wind field could be improved if instead three fully steerable Lidars were simultaneously measuring from three different locations around the air volume of interest. Based on this concept, a ground-based Doppler Lidar Windscanner facility capable of providing the wind vector in several hundred locations each second is currently under development within a Ris� DTU project that aims at providing a useful research tool in the field of wind power meteorology for the decade ahead. A field campaign inter-comparison of the turbulence and the wind vector measured by a sonic anemometer and by three Lidars staring from three different directions towards the location of the sonic anemometer has already recently provided some initial prospective results of this approach to measure the 3D wind and turbulence field.
Module Handbook Specialisation Wind Energy
Habel, Annegret
;Specialisation Wind Energy, NTU Athens, 2nd Semester Module 1/Wind Energy: Wind potential, Aerodynamics & Loading of Wind Turbines Module name: Wind potential, Aerodynamics & Loading of Wind Turbines Section Classes Evaluation of Wind Energy Potential Wind turbine Aerodynamics Static and dynamic Loading of Wind turbines
Solar angles revisited using a general vector approach
Parkin, Robert E. [Department of Mechanical Engineering, University of Massachusetts, 1 University Avenue, Lowell, MA 01854 (United States)
Rather than follow the standard technique using direction cosines or major axes vectors to define the angles of the sun, we develop the necessary formulae from a 3-tuple vector based analysis. The direction of the sun with respect to a Cartesian coordinate system is defined as a unit vector, as is the orthogonal to a surface intended to accept solar radiation. The vector formulation is powerful and universal. More importantly, the diagrams used to describe the relative motion of the sun with respect to the Earth are quite simple, leading to less confusion when translating the geometry to algebra. An interesting result on the change in solar angle with time follows. (author)
Landscape externalities from onshore wind power
J�rgen Meyerhoff; Cornelia Ohl; Volkmar Hartje
The expansion of renewable energy is a central element of the German Federal Government's climate and energy policy. The target for 2020 is to produce 30% of the electricity from renewable energies. Wind power has been selected to be a major contributor to this change. Replacing old wind turbines by modern ones and building new turbines on land will be
Wind-Blown Sand: Threshold of Motion�
Swann, Christy Michelle
The fluid threshold for wind-blown sand is the minimum shear velocity required to initiate grain movement by the force of the wind alone, and is used to predict dust emission and landform change in sandy environments. R.A. ...
Appel, A.W.; Bendiksen, A.
Garbage collection can be done in vector mode on supercomputers like the Cray-2 and the Cyber 205. Both copying collection and mark-and-sweep can be expressed as breadth-first searches in which the queue can be processed in parallel. The authors have designed a copying garbage collector whose inner loop works entirely in vector mode. The only significant limitation of the algorithm is that if the size of the records is not constant, the implementation becomes much more complicated. The authors give performance measurements of the algorithm as implemented for Lisp CONS cells on the Cyber 205. Vector-mode garbage collection performs up to 9 times faster than scalar-mode collection.
ERIC Educational Resources Information Center
Swapp, Andy; Schreuders, Paul; Reeve, Edward
Many people use wind to help meet their needs. Over the years, people have been able to harness or capture the wind in many different ways. More recently, people have seen the rebirth of electricity-generating wind turbines. Thus, the age-old argument about technology being either good or bad can also be applied to the wind. The wind can be a�
ERIC Educational Resources Information Center
Liming, Drew; Hamilton, James
As a common form of renewable energy, wind power is generating more than just electricity. It is increasingly generating jobs for workers in many different occupations. Many workers are employed on wind farms: areas where groups of wind turbines produce electricity from wind power. Wind farms are frequently located in the midwestern, western, and�
Wind field variability in high-resolution simulations for wind energy forecasts and resource assessment
NASA Astrophysics Data System (ADS)
Marjanovic, N.; Chow, F. K.; Wharton, S.; Lundquist, J. K.
Wind farm resource assessment, operational wind power forecasting, and wind turbine micrositing may benefit from high-resolution simulations of atmospheric flow over complex terrain. Domains can be refined from mesoscale to finer scales using grid nesting to adequately resolve turbulence and terrain in the atmospheric boundary layer. In previous work, we showed that nesting down to fine resolutions (~100 m horizontal spacing) using the WRF model does not clearly improve mean wind forecasts for our case study wind farm when modeling either synoptically or locally driven events. Differences due to increased vertical resolution or using one- vs. two-way nesting were also minimal. The LES models we tested gave similar results and were only slightly closer to the observations than the RANS models. For this particular domain, it appears that key topographic features are well resolved even at coarser resolutions, so that there is minimal change in mean winds at finer resolutions. In this work, we investigate temporal and spatial variability of predicted fields to gain further insight into possible differences due to changes in grid configuration. We also perform week-long simulations at fine resolutions of 300 or 100 meters to determine if we can obtain more detailed results for wind energy resource assessment. High-resolution representation of the spatial structure of the wind flow might be able to better capture variations in wind velocity that are relevant to wind resource assessment. Improved turbulence closure schemes will also be tested and should be able to better capture the fluctuations in the wind fields which may contribute to turbine fatigue. Long term, fine resolution runs should provide more insight into wind patterns and yield frequency distributions of wind speed, wind shear, TKE, and other factors that are invaluable to wind farm operators in determining appropriate sites for turbines and times for greatest power output.
Free-Spinning Wind-Tunnel Tests of a Low-Wing Monoplane with Systematic Changes in Wings and Tails V : Effect of Airplane Relative Density
NASA Technical Reports Server (NTRS)
Seidman, Oscar; Neihouse, A I
The reported tests are a continuation of an NACA investigation being made in the free-spinning wind tunnel to determine the effects of independent variations in load distribution, wing and tail arrangement, and control disposition on the spin characteristics of airplanes. The standard series of tests was repeated to determine the effect of airplane relative density. Tests were made at values of the relative-density parameter of 6.8, 8.4 (basic), and 12.0; and the results were analyzed. The tested variations in the relative-density parameter may be considered either as variations in the wing loading of an airplane spun at a given altitude, with the radii of gyration kept constant, or as a variation of the altitude at which the spin takes place for a given airplane. The lower values of the relative-density parameter correspond to the lower wing loadings or to the lower altitudes of the spin.
Alex Harvey; Engelbert L. Schucking; Eugene J. Surowitz
Courses in introductory special and general relativity have increasingly become part of the curriculum for upper-level undergraduate physics majors and master's degree candidates. One of the topics rarely discussed is symmetry, particularly in the theory of general relativity. The principal tool for its study is the Killing vector. We provide an elementary introduction to the concept of a Killing vector field, its properties, and as an example of its utility apply these ideas to the rigorous determination of gravitational and cosmological redshifts.
How the wind climate of the Carpathian basin will change in the 21st century on the basis of PRECIS simulations?
Laura Dobor; Rita Pongracz; Judit Bartholy; Ildiko Pieczka
High resolution model results are essential for the generation of national climate change scenarios, as it is recommended by the United Nations Development Programme (UNDP). For analyzing the possible regional climate change in the Carpathian Basin, we have adapted the model PRECIS at the Department of Meteorology, E�tv�s Lor�nd University. The model PRECIS is a hydrostatic regional climate model HadRM3P
NASA Technical Reports Server (NTRS)
2003-01-01[figure removed for brevity, see original site] Released 17 September 2003Bright wind streaks are present in the lee of craters and other obstacles in this image, located in Sinus Sabaeus, near the Martian equator. These streaks indicate that the local winds blow from the northeast (upper right in the image). The brightness of the streaks indicates that either bright material has been deposited in the lee of the craters, or that the surface has eroded preferentially in the lee of craters, exposing an underlying bright material. Because the streaks are bright regardless of the surrounding surface brightness, the first hypothesis most likely. The streaks probably all represent deposits of the same bright material that settled out of the atmosphere in the wind shelter provided by topographic peaks.Image information: VIS instrument. Latitude -6.3, Longitude 14.1 East (345.9 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
NSDL National Science Digital Library
In this online, interactive module, students learn about the using successive satellite observations of clouds to determine wind direction and speed. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.
Traudt, R.F.
This patent describes a wind turbine device having a main rotatable driven shaft, elongated blades operatively mounted on the main shaft for unitary rotation with the main shaft. The blade extends substantially radially away from the main shaft and is adapted to fold downwind under naturally occurring forces and simultaneously feather in direct response to the folding movement. A means associated with the blades is included for increasing the rate of fold relative to the rate of feather as the speed of rotation increases.
Honeycutt, R. K. [Astronomy Department, Indiana University, Swain Hall West, Bloomington, IN 47405 (United States); Kafka, S. [Department of Terrestrial Magnetism, Carnegie Institute of Washington, 5241 Broad Branch Road NW, Washington, DC 2001 (United States); Robertson, J. W., E-mail: email@example.com, E-mail: email@example.com, E-mail: firstname.lastname@example.com [Department of Physical Sciences, Arkansas Tech University, 1701 North Boulder Avenue, Russellville, AR 72801-2222 (United States)
Sequences of spectra of the nova-like cataclysmic variable (CV) BZ Cam were acquired on nine nights in 2005-2006 in order to study the time development of episodes of wind activity known to occur frequently in this star. We confirm the results of Ringwald and Naylor that the P-Cygni absorption components of the lines mostly evolve from higher expansion velocity to lower velocity as an episode progresses. We also commonly find blueshifted emission components in the H{alpha} line profile, whose velocities and durations strongly suggest that they are also due to the wind. Curiously, Ringwald and Naylor reported common occurrences of redshifted H{alpha} emission components in their BZ Cam spectra. We have attributed these emission components in H{alpha} to occasions when gas concentrations in the bipolar wind (both front side and back side) become manifested as emission lines as they move beyond the disk's outer edge. We also suggest, based on changes in the P-Cygni profiles during an episode, that the progression from larger to smaller expansion velocities is due to the higher velocity portions of a wind concentration moving beyond the edge of the continuum light of the disk first, leaving a net redward shift of the remaining absorption profile. We derive a new orbital ephemeris for BZ Cam, using the radial velocity of the core of the He I {lambda}5876 line, finding P = 0.15353(4). Using this period, the wind episodes in BZ Cam are found to be concentrated near the inferior conjunction of the emission line source. This result helps confirm that the winds in nova-like CVs are often phase dependent, in spite of the puzzling implication that such winds lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an initial boost by acting on gas that has been lifted above the disk by the interaction of the accretion stream with the disk, thereby imposing flickering timescales onto the wind events, as well as leading to an orbital modulation of the wind due to the non-axisymmetric nature of the stream/disk interaction. Simultaneous photometry and spectroscopy were acquired on three nights in order to test the possible connection between flickering continuum light and the strength of the front-side wind. We found strong agreement on one night, some agreement on another, and no agreement on the third. We suggest that some flickering events lead to only back-side winds which will not have associated P-Cygni profiles.
Winds Report: Measuring Ocean Winds from Space
NSDL National Science Digital Library
Users of this resource can access imagery and animations made from scatterometry data from the SeaWinds instrument, which flies aboard the QuikSCAT satellite. A scatterometer is a radar instrument which bounces electromagnetic energy off the surface of the ocean. Combining the radar return from the same patch of ocean, but as seen from from different directions, allows the calculation of both wind speed and wind direction. In the animations, the background color shows the wind speed: blue is low wind speed and yellow or magenta, high. The direction of the wind field is shown by the direction of motion of imaginary "particles" in the animation.
Wind tower augmentation of wind turbines
NASA Astrophysics Data System (ADS)
Bahadori, M. N.
The operating principle of the 'Baud-Geers' wind towers traditionally used in Iran for ventilation and passive cooling of architectural structures is presently adapted to house a vertical axis wind turbine. Unlike annular diffuser-augmented, horizontal axis wind turbines, the 'wind tower' does not have to be trained into the wind and generates less noise. It may also be either free standing or incorporated into the structure of existing buildings. Attention is given to the continuity and energy equations of this system, and to the results of wind tunnel model testing which ascertained turbine load factor and augmentation ratio.
Wind for Schools (Presentation)
Kelly, M.
Schools are key to achieving the goal of producing 20% of the nation's electricity demand. Most significantly, schools are training the scientists, technicians, businesspeople, decisionmakers, and teachers of the future. What students learn and believe about wind energy will impact the United States' ability to create markets and policy, develop and improve technology, finance and implement projects, and create change in all of our public and private institutions. In the nearer term, school districts have large facility costs, electrical loads, and utility costs. They are always in search of ways to reduce costs or obtain revenue to improve educational programs. Schools value teaching about the science and technology of renewable energy. They are important opinion leaders, particularly in rural communities. And their financial structures are quite different from other institutions (funding, incentives, restrictions, etc.). Learning objectives: The presentation will use case studies, project experience, and discussion with the audience to convey the current status of wind energy applications and education in U.S. schools and understanding of the elements that create a successful school wind energy project. The presentation will provide attendees with a background in the current level of knowledge and generate discussion on several themes.
NASA Astrophysics Data System (ADS)
Lee, S.; Churchfield, M.; Sirnivas, S.; Moriarty, P.; Nielsen, F. G.; Skaare, B.; Byklum, E.
A team of researchers from the National Renewable Energy Laboratory and Statoil used large-eddy simulations to numerically investigate the merging wakes from upstream offshore wind turbines. Merging wakes are typical phenomena in wind farm flows in which neighboring turbine wakes consolidate to form complex flow patterns that are as yet not well understood. In the present study, three 6-MW turbines in a row were subjected to a neutrally stable atmospheric boundary layer flow. As a result, the wake from the farthest upstream turbine conjoined the downstream wake, which significantly altered the subsequent velocity deficit structures, turbulence intensity, and the global meandering behavior. The complexity increased even more when the combined wakes from the two upstream turbines mixed with the wake generated by the last turbine, thereby forming a �triplet� structure. Although the influence of the wake generated by the first turbine decayed with downstream distance, the mutated wakes from the second turbine continued to influence the downstream wake. Two mirror-image angles of wind directions that yielded partial wakes impinging on the downstream turbines yielded asymmetric wake profiles that could be attributed to the changing flow directions in the rotor plane induced by the Coriolis force. The turbine wakes persisted for extended distances in the present study, which is a result of low aerodynamic surface roughness typically found in offshore conditions.
Scientific Impacts of Wind Direction Errors
NASA Technical Reports Server (NTRS)
Liu, W. Timothy; Kim, Seung-Bum; Lee, Tong; Song, Y. Tony; Tang, Wen-Qing; Atlas, Robert
An assessment on the scientific impact of random errors in wind direction (less than 45 deg) retrieved from space-based observations under weak wind (less than 7 m/s ) conditions was made. averages, and these weak winds cover most of the tropical, sub-tropical, and coastal oceans. Introduction of these errors in the semi-daily winds causes, on average, 5% changes of the yearly mean Ekman and Sverdrup volume transports computed directly from the winds, respectively. These poleward movements of water are the main mechanisms to redistribute heat from the warmer tropical region to the colder high- latitude regions, and they are the major manifestations of the ocean's function in modifying Earth's climate. Simulation by an ocean general circulation model shows that the wind errors introduce a 5% error in the meridional heat transport at tropical latitudes. The simulation also shows that the erroneous winds cause a pile-up of warm surface water in the eastern tropical Pacific, similar to the conditions during El Nino episode. Similar wind directional errors cause significant change in sea-surface temperature and sea-level patterns in coastal oceans in a coastal model simulation. Previous studies have shown that assimilation of scatterometer winds improves 3-5 day weather forecasts in the Southern Hemisphere. When directional information below 7 m/s was withheld, approximately 40% of the improvement was lost
Global Trends in Wind Speed and Wave Height
I. R. Young; S. Zieger; A. V. Babanin
Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in
Scan patterns and accuracy of a Radar Wind Sensor (RAWS)
NASA Technical Reports Server (NTRS)
Song, Shuxian; Beh, Beng; Moore, Richard K.
The Radar Wind Sensor (RAWS) was proposed as a complement to laser wind sensors, allowing coverage in cloudy regions excluded from laser coverage. Previous University of Kansas studies showed the feasibility of the wind measurement at various levels in the atmosphere and indicated that RAWS can also measure rain rates and ocean-surface winds. Here we discuss measurement of the wind vector in terms of the scan patterns for a conically scanned antenna. By using many measurements from cells about 66 km square and 132 km square, a least-squares algorithm gives results that are reasonable for insertion into global atmospheric models. For RAWS to be used successfully as a complement to a laser wind sensor, the design of the two sensors should be integrated and radial velocity measurements in a given atmospheric cell should be combined to get the most accurate results.
The Solar Wind, CMEs and the Origins of Heliospheric Activity
The Solar Wind, CMEs and the Origins of Heliospheric Activity Peter T. Gallagher School of Physics release o Coronal holes o Source of high-speed solar wind #12;firstname.lastname@example.com #12;#12;email@example.com #12;#12;The solar wind o Biermann (1951): comets showed excess ionization and abrupt changes
Effects of Topography on Assessing Wind Farm Impacts Using
Zhou, Liming
Effects of Topography on Assessing Wind Farm Impacts Using MODIS Data Liming Zhou* Department) there is a pattern of LST change associated with the de- velopment of wind farms and (ii) the warming effect over wind farms reported previously is an artifact of varied surface topography. Spatial pattern and time
Transformer winding diagnosis using comparison of transfer function coefficients
Mehdi Bigdeli; Mehdi Vakilian; Ebrahim Rahimpour; Davood Azizian
In this work, a new model of transformer winding is developed. The components in the model are determined by the geometric and electric data of the winding. Under different degrees of axial displacement and radial deformation in the winding, circuit parameters in the model will be changed and thus the character of the circuit will be influenced. After acquiring the
Wind energy feasibility study for city of Shahrbabak in Iran
A. Mostafaeipour; A. Sedaghat; A. A. Dehghan-Niri; V. Kalantar
Climate change, global warming, and the recent worldwide economic crisis have emphasized the need for low carbon emissions while also ensuring economic feasibility. In this paper, the status and wind power potential of the city of Shahrbabak in Kerman province in Iran was investigated. The technical and economical feasibility of wind turbine installation is presented. The potential of wind power
Killing vectors and anisotropy
J. P. Krisch; E. N. Glass
We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string.
Killing vectors and anisotropy
Krisch, J. P.; Glass, E. N. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
We consider an action that can generate fluids with three unequal stresses for metrics with a spacelike Killing vector. The parameters in the action are directly related to the stress anisotropies. The field equations following from the action are applied to an anisotropic cosmological expansion and an extension of the Gott-Hiscock cosmic string.
Singular Vectors' Subtle Secrets
ERIC Educational Resources Information Center
James, David; Lachance, Michael; Remski, Joan
Social scientists use adjacency tables to discover influence networks within and among groups. Building on work by Moler and Morrison, we use ordered pairs from the components of the first and second singular vectors of adjacency matrices as tools to distinguish these groups and to identify particularly strong or weak individuals.
NASA Technical Reports Server (NTRS)
Garay, Michael J.; Mazzoni, Dominic; Davies, Roger; Wagstaff, Kiri
Support Vector Machines (SVMs) are a type of supervised learning algorith,, other examples of which are Artificial Neural Networks (ANNs), Decision Trees, and Naive Bayesian Classifiers. Supervised learning algorithms are used to classify objects labled by a 'supervisor' - typically a human 'expert.'.
ERIC Educational Resources Information Center
Dean, Richard A.
The author shows that the set of all sequences in which each term is the sum of the two previous terms forms a vector space of dimension two. He uses this result to obtain the formula for the Fibonacci sequence and applies the same technique to other linear recursive relations. (MM)
Vector Autoregressions and Reality
David E. Runkle
This article questions the statistical significance of variance decompositions and impulse response functions for unrestricted vector autoregressions. It suggests that previous authors have failed to provide confidence intervals for variance decompositions and impulse response functions. Two methods of computing such confidence intervals are developed: first, using a normal approximation; second, using bootstrapped resampling. An example from Sims's work is used
Study on extreme turbulence wind conditions of multibody dynamics simulation for MW-class wind turbine
NASA Astrophysics Data System (ADS)
Wu, P.; Li, C.; Ye, Z.
Parametric modeling of NREL 5MW wind turbine was set up for multi-body dynamics simulation by the TurbSim, AeroDyn, FAST (fatigue, aerodynamics, structures, and turbulence) software respectively. According to the analysis of the characteristics of wind in the space discrete point, using TurbSim to establish the steady-state wind and random changes with time and space wind. Based on the AeroDyn software, which can coupled to FAST, we calculated the aerodynamic load. Loading the aerodynamic data which has been calculated, FAST can establish a fully parameterized simulation model. Making a comparison of the results obtained by FAST in 3 different wind conditions, the different of dynamic responses of the structure were obtained. The results obtained by FAST have some meaning in the study of wind turbine under extreme turbulence wind conditions.
Learning to forecast wind at remote sites for wind energy applications. Final report
Notis, C.; Trettel, D.W.; Aquino, J.T.; Piazza, T.R.; Taylor, L.E.; Trask, D.C.; Wegley, H.L.; Miller, A.H.
Observed wind patterns are correlated with synoptic or mescoscale weather systems. Six sites selected for analysis include Montauk Point, New York; Boone, North Carolina; Ludington, Michigan; Clayton, New Mexico; Amarillo, Texas; and San Gorgonio Pass, California. Objectives of the analysis are: to identify synoptic and/or mesoscale weather patterns that are associated with recognizable wind events at the sites; to define a set of criteria that uniquely describes such weather patterns; to estimate the reliability (accuracy) of forecasting rules derived from the association of weather patterns and site winds; and to attempt to separate any mesoscale effects of local topography from the synoptic-scale effects. One-to-one mapping of wind regimes onto synoptic types was not found. It was concluded that four factors should be examined when stratifying wind regimes: synoptic situation, descriptive climatology, pressure gradient vector, and winds aloft. The wind forecasting approach developed was intended for forecasting hourly average winds out to the 24 hour or possibly 36 hour time horizon. (LEW)
Wind-Flow Dynamics Over a Vineyard
NASA Astrophysics Data System (ADS)
Chahine, Ali; Dupont, Sylvain; Sinfort, Carole; Brunet, Yves
Wind-flow dynamics has been extensively studied over horizontally uniform canopies, but agricultural plantations structured in rows such as vineyards have received less attention. Here, the wind flow over a vineyard is studied in neutral stratification from both large-eddy simulation (LES) and in situ measurements. The impact of row structure on the wind dynamics is investigated over a range of wind directions from cross-row to down-row, and a typical range of row aspect ratio (row separation/height ratio). It is shown that the mean flow over a vineyard is similar to that observed in uniform canopies, especially for wind directions from cross-row to diagonal. For down-row winds, the mean flow exhibits noticeable spatial variability across each elementary row-gap pattern, as the wind is channeled in the inter-row. This spatial variability increases with the aspect ratio. With down-row winds the turbulent structures are also more intermittent and generate larger turbulent kinetic energy and momentum flux. The displacement height and roughness length of the vineyard vary with the aspect ratio in a way similar to their variation with canopy density in uniform canopies. Both parameters take smaller values in down-row wind flow, for which the canopy appears more open. The analysis of velocity spectra and autocorrelation functions shows that vineyard canopies share similar features to uniform canopies in terms of turbulent coherent structures, with only minor changes with wind direction.
Statewide Air Emissions Calculations From Wind and Other Renewables: Summary Report�
Haberl, J. S.; Baltazar, J. C.; Mao, C.; Culp, C.; Yazdani, B.; Claridge, D.; Do, S.
Phase Change Material PV Photovoltaic RMSE Root Mean Square Error SHGC Solar Heat Gain Coefficient SWH Solar Water Heating VAWT Vertical Axis Wind Turbine vii VBDD model Variable-Base Degree... to produce electricity, the wind power system is called a wind turbine. Wind turbines have two general types: horizontal axis wind turbines (HAWTs) with its blades rotating on an axis parallel to the ground; vertical axis wind turbines (VAWTs) with its...
The Extinction of Dengue through Natural Vulnerability of Its Vectors
Craig R. Williams; Christie A. Bader; Michael R. Kearney; Scott A. Ritchie; Richard C. Russell
BackgroundDengue is the world's most important mosquito-borne viral illness. Successful future management of this disease requires an understanding of the population dynamics of the vector, especially in the context of changing climates. Our capacity to predict future dynamics is reflected in our ability to explain the significant historical changes in the distribution and abundance of the disease and its vector.Methodology\\/Principal
Pallabazzer, R. (Univ. della Calabria (Italy)); Gabow, A.A. (Somali National Univ., Mogadisho (Somalia))
The results of wind energy research in Somalia are presented. The wind resource appears to be suitable for power production on 85% of the country, very intense on 10% and uniform on 70%, being regular throughout. Two areas of different wind regimes have been identified and characterized; the wind-distribution characteristics of 11 sites are presented and discussed, together with the territorial maps of the wind intensity and of the wind energy.
Horizontal Wind Measurements using the HARLIE Holographic Lidar
NASA Technical Reports Server (NTRS)
Wilkerson, Thomas; Andrus, Ionio; Sanders, Jason; Schwemmer, Geary; Miller, David; Guerra, David; Starr, David OC. (Technical Monitor)
We report the results of three campaigns in which the horizontal wind vector at cloud altitudes was measured using the holographic, conical-scan lidar HARLIE in its nadir-viewing mode. Measurements were made during the HOLO-1 and -2 tests in Utah and New Hampshire in March and June 1999, respectively, and at the DoE-ARM site in Oklahoma in September/October 2000. A novel algorithm facilitates the wind vector analysis of the HARLIE data. Observed wind velocity and direction were compared with radiosonde records and with other data obtained from video cloud imagery and independent lidar ranging. The results demonstrate good agreement between HARLIE data and the results of other methods. The conically scanning holographic lidar opens up new possibilities for obtaining the vertical profile of horizontal winds.
Massachusetts at Amherst, University of
of Massachusetts, Amherst in the course of performing work sponsored by the Renewable Energy Trust (RET...................................................................................................................... 9 Wind Speed Time Series........................................................................................................... 10 Wind Speed Distributions
This bibliography is designed to help the reader search for information on wind energy. The bibliography is intended to help several audiences, including engineers and scientists who may be unfamiliar with a particular aspect of wind energy, university researchers who are interested in this field, manufacturers who want to learn more about specific wind topics, and librarians who provide information to their clients. Topics covered range from the history of wind energy use to advanced wind turbine design. References for wind energy economics, the wind energy resource, and environmental and institutional issues related to wind energy are also included.
Wind Power Today: Federal Wind Program Highlights
Not Available
Wind Power Today is an annual publication that provides an overview of the wind research conducted under the U.S. Department of Energy's Wind and Hydropower Technologies Program. The purpose of Wind Power Today is to show how DOE supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers about the advantages and potential for widespread deployment of wind energy; explain the program's objectives and goals; describe the program's accomplishments in research and application; examine the barriers to widespread deployment; describe the benefits of continued research and development; facilitate technology transfer; and attract cooperative wind energy projects with industry.
Wind Power! Designing a Wind Turbine
NSDL National Science Digital Library
Students learn how engineers transform wind energy into electrical energy by building their own miniature wind turbines and measuring the electrical current it produces. They explore how design and position affect the electrical energy production.
Numerical study of ocean wave effect on offshore wind farm
NASA Astrophysics Data System (ADS)
Shen, Lian; Yang, Di; Meneveau, Charles
Wind power at sea has become increasingly important in renewable energy study. For energy harvesting, winds over oceans have many advantages over winds on land, for example, larger and open surface area, faster wind speed, and more wind resource close to high population regions. On the other hand, the presence of ocean waves introduces complexities to wind turbines. There is a critical need to study the dynamical interactions among marine atmospheric boundary layer, ocean wave field, and floating turbines. In this research, we study offshore wind farm by performing large-eddy simulations for winds coupled with potential-flow-theory based simulations for broadband irregular waves, with the wind turbines represented by an actuator disk model. Our results show that windseas at different development stages result in different sea-surface roughness and have an appreciable effect on wind profile and the energy extraction rate of the turbines. If swells are present, swell-to-wind momentum and energy transfer further changes the wind field to introduce oscillations in as well as modify the mean of the wind power. Wind power at sea has become increasingly important in renewable energy study. For energy harvesting, winds over oceans have many advantages over winds on land, for example, larger and open surface area, faster wind speed, and more wind resource close to high population regions. On the other hand, the presence of ocean waves introduces complexities to wind turbines. There is a critical need to study the dynamical interactions among marine atmospheric boundary layer, ocean wave field, and floating turbines. In this research, we study offshore wind farm by performing large-eddy simulations for winds coupled with potential-flow-theory based simulations for broadband irregular waves, with the wind turbines represented by an actuator disk model. Our results show that windseas at different development stages result in different sea-surface roughness and have an appreciable effect on wind profile and the energy extraction rate of the turbines. If swells are present, swell-to-wind momentum and energy transfer further changes the wind field to introduce oscillations in as well as modify the mean of the wind power. DY and LS acknowledge the support of NSF-CBET-1341062. CM acknowledges the support of NSF-AGS-1045189 and NSF-OISE-1243482.
Helium and hydrogen velocity differences in the solar wind
J. R. Asbridge; S. J. Bame; W. C. Feldman; M. D. Montgomery
Scalar and vector velocity differences between helium and hydrogen ions in the solar wind measured with the Los Alamos plasma analyzers on Imp 6 and 7 are presented and interpreted. From the bulk speeds and azimuthal components of flow direction for both types of ions the ecliptic projection of the helium to hydrogen velocity difference vector v\\/subo\\/\\/subp\\/ is determined. Short-term
NOSS-SCAT wind direction alias removal
NASA Technical Reports Server (NTRS)
Shanmugan, K. S.; Narayanan, V.; Stiles, J.
The use of automated algorithms for removing aliases in NOSS-SCAT data is reported. The algorithms used for alias removal consist of histogram analysis, local averaging and curve fitting. The histogram analysis is used to determine the degree of homogeneity of the wind field defined by the largest probability alias vector at each grid point. The alias directions are compared with the preferred direction at each grid location and one of the multiple aliases is chosen as the true direction.
Wind profiles for large wind turbines
C. B. Hasager; A. Pe�a; S.-E. Gryning; T. Mikkelsen; M. Courtney
The 12MW project aimed to describe wind profiles and turbulence at levels high in the atmosphere where large wind turbines operate. During the project observations up to 180 m above sea level were collected using mast and lidar offshore in the North Sea at the Horns Rev wind farm in 2006. Later also land-based observations were collected at the coastal
On-Chip Vector Coprocessor Sharing for Multicores Spiridon F. Beldianu and Sotirios G. Ziavras
Ziavras, Sotirios G.
On-Chip Vector Coprocessor Sharing for Multicores Spiridon F. Beldianu and Sotirios G. Ziavras.edu, firstname.lastname@example.com Abstract-- For most of the applications that make use of a vector coprocessor to vector-length changes in dynamic environments. The motivation of our work stems from (a) the mandate
Increasing Arctic sea ice export driven by stronger winds
NASA Astrophysics Data System (ADS)
Sorteberg, A.; Smedsrud, L. H.; Sirevaag, A.; Kloster, K.
Arctic sea ice area has decreased steadily over the last three decades. A thinner and more seasonal Arctic ice cover, related to increased long wave radiation, has become evident. Changes in circulation, including drift patterns of the Arctic pack ice, have been less obvious. Arctic sea ice export estimates have been hampered by low resolution spatial and temporal satellite imagery, especially during summer, making accurate detection difficult. Here we present a new ice area export dataset calculated from sea ice motion and concentration profiles along 79N. Ice drift vectors are calculated from ice feature displacement using Envisat ASAR WideSwath images every 3 days from 2004 while ice concentration is based on DMSP F13 SSMI and AQUA AMSR-E brightness temperature data. The two data sets are combined to give the ice-area flux in consecutive 3-day periods, uninterrupted year-round coverage along 79N. It is shown that sea ice export variability is closely linked to the geostrophic wind in the Fram Strait (correlation of 0.84). Using geostrophic winds from reanalysis back to the 1950s as a proxy for ice export indicates that the Arctic sea ice has annually lost an increasing area since the 1950's driven by stronger winds. Ice concentration has decreased slightly, but does not contribute significantly. The ice export has overall increased by ~25% over the period. Using cyclone tracking the changes in winds seems directly related to a higher low pressure activity in the Nordic Seas. Our results demonstrate that the changes in atmospheric circulation over the Arctic and sub-Arctic have contributed to a trend in the Fram Strait ice export. The Fram Strait between Greenland and Svalbard with average sea ice concentration for summer (red, June through August) and winter (black, January through March). Solid lines are 50%, dashed lines are 15%. Above mean southward ice drift across 79N from August 2004 to July 2010 in 1 degree bins based on SAR imagery, and mean ice concentration from SSMI data. The ice area export is found by multiplying the ice drift and ice concentrations. Yellow circles show locations for surface pressure data used.
Variable diameter wind turbine rotor blades
Jamieson, Peter McKeich; Hornzee-Jones, Chris; Moroz, Emilian M.; Blakemore, Ralph W.
A system and method for changing wind turbine rotor diameters to meet changing wind speeds and control system loads is disclosed. The rotor blades on the wind turbine are able to adjust length by extensions nested within or containing the base blade. The blades can have more than one extension in a variety of configurations. A cable winching system, a hydraulic system, a pneumatic system, inflatable or elastic extensions, and a spring-loaded jack knife deployment are some of the methods of adjustment. The extension is also protected from lightning by a grounding system.
Insect Vectors of Human Pathogens
NSDL National Science Digital Library
Four orders of insects (Hemiptera, Phthiraptera, Diptera, and Siphonaptera) are covered detailing vector species along with their pathogens of human importance. Links to pathogens as well as vectors are highlighted (some of these are CDC, and WHO).
Nonviral Vectors for Gene Delivery
Baoum, Abdulgader Ahmed
The development of nonviral vectors for safe and efficient gene delivery has been gaining considerable attention recently. An ideal nonviral vector must protect the gene against degradation by nuclease in the extracellular matrix, internalize...
Review of Wind Energy Forecasting Methods for Modeling Ramping Events
Wharton, S; Lundquist, J K; Marjanovic, N; Williams, J L; Rhodes, M; Chow, T K; Maxwell, R
Tall onshore wind turbines, with hub heights between 80 m and 100 m, can extract large amounts of energy from the atmosphere since they generally encounter higher wind speeds, but they face challenges given the complexity of boundary layer flows. This complexity of the lowest layers of the atmosphere, where wind turbines reside, has made conventional modeling efforts less than ideal. To meet the nation's goal of increasing wind power into the U.S. electrical grid, the accuracy of wind power forecasts must be improved. In this report, the Lawrence Livermore National Laboratory, in collaboration with the University of Colorado at Boulder, University of California at Berkeley, and Colorado School of Mines, evaluates innovative approaches to forecasting sudden changes in wind speed or 'ramping events' at an onshore, multimegawatt wind farm. The forecast simulations are compared to observations of wind speed and direction from tall meteorological towers and a remote-sensing Sound Detection and Ranging (SODAR) instrument. Ramping events, i.e., sudden increases or decreases in wind speed and hence, power generated by a turbine, are especially problematic for wind farm operators. Sudden changes in wind speed or direction can lead to large power generation differences across a wind farm and are very difficult to predict with current forecasting tools. Here, we quantify the ability of three models, mesoscale WRF, WRF-LES, and PF.WRF, which vary in sophistication and required user expertise, to predict three ramping events at a North American wind farm.
Some experiences with Krylov vectors and Lanczos vectors
NASA Technical Reports Server (NTRS)
Craig, Roy R., Jr.; Su, Tzu-Jeng; Kim, Hyoung M.
This paper illustrates the use of Krylov vectors and Lanczos vectors for reduced-order modeling in structural dynamics and for control of flexible structures. Krylov vectors and Lanczos vectors are defined and illustrated, and several applications that have been under study at The University of Texas at Austin are reviewed: model reduction for undamped structural dynamics systems, component mode synthesis using Krylov vectors, model reduction of damped structural dynamics systems, and one-sided and two-sided unsymmetric block-Lanczos model-reduction algorithms.
Kernel uncorrelated optimal discriminant vectors
NASA Astrophysics Data System (ADS)
Yang, Yuwang; Yang, Jingyu; Jin, Zhong
We construct kernel uncorrelated optimal discriminant vectors(KUODV) for non-linear feature extraction and discrimination. Employing the uncorrelated optimal discriminant vectors(UODV) and kernel method, we propose non-linear generalization of uncorrelated optimal discriminant vectors, and then enhance the performance of original UODV. Human face recognition experiments show the utility of our new method.
Statistical analysis of cointegration vectors
Soren Johansen
We consider a nonstationary vector autoregressive process which is integrated of order 1, and generated by i.i.d. Gaussian errors. We then derive the maximum likelihood estimator of the space of cointegration vectors and the likelihood ratio test of the hypothesis that it has a given number of dimensions. Further we test linear hypotheses about the cointegration vectors. The asymptotic distribution
Nonlinear Vector Analyzers [review of \\
Alfy Riddle
This book offers the reader a tour of how nonlinear vector analyzers work and how they can be used in circuit design. It contains nine chapters and no appendices. The two key chapters describe nonlinear vector instrumentation and describe behavioral modeling. In many places, the book goes into lengthy descriptions of nonlinear vector analyzer calibration, device heating, semiconductor traps, and
Student Preconceptions about Vector Kinematics.
ERIC Educational Resources Information Center
Aguirre, Jose M.
Examines preconceptions regarding several implicit vector characteristics that 15- to 17-year-old students possess just before taking their first physics course. Shows seven vector characteristics and three tasks for interviewing students. Presents the most common student preconceptions regarding each of the implicit vector characteristics. (YP)
Vector spaces Linear independence & bases
Geuvers, Herman
Vector spaces Linear independence & bases Linear maps Linear maps and matrices Radboud University Nijmegen Matrix Calculations: Vector Spaces and Linear Maps H. Geuvers Institute for Computing: fall 2014 Matrix Calculations 1 / 40 #12;Vector spaces Linear independence & bases Linear maps Linear
Linfan Mao
A Smarandache multi-space is a union of $n$ spaces $A_1,A_2,..., A_n$ with some additional conditions holding. Combining Smarandache multi-spaces with linear vector spaces in classical linear algebra, the conception of multi-vector spaces is introduced. Some characteristics of a multi-vector space are obtained in this paper.
Support vector networks Sance svn
Bouzy, Bruno
Support vector networks S�ance � svn � de l'UE � apprentissage automatique � Bruno Bouzy firstname.lastname@example.com www.mi.parisdescartes.fr/~bouzy #12;Support-vector networks Reference � These slides present the following paper: � C.Cortes, V.Vapnik, � support vector networks �, Machine Learning (1995
V. N. Borodikhin
We proposed a gravitation theory based on an analogy with electrodynamics on the basis of a vector field. For the first time, to calculate the basic gravitational effects in the framework of a vector theory of gravity, we use a Lagrangian written with gravitational radiation neglected and generalized to the case of ultra-relativistic speeds. This allows us to accurately calculate the values of all three major gravity experiments: the values of the perihelion shift of Mercury, the light deflection angle in the gravity field of the Sun and the value of radar echo delay. The calculated values coincide with the observed ones. It is shown that, in this theory, there exists a model of an expanding Universe.
Maximally symmetric vector propagator
Tsamis, N. C.; Woodard, R. P. [Department of Physics, University of Crete, GR-710 03 Heraklion (Greece); Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)
We derive the propagator for a massive vector field on a de Sitter background of arbitrary dimension. This propagator is de Sitter invariant and possesses the proper flat space-time and massless limits. Moreover, the retarded Green's function inferred from it produces the correct classical response to a test source. Our result is expressed in a tensor basis which is convenient for performing quantum-field-theory computations using dimensional regularization.
NASA Technical Reports Server (NTRS)
Chipman, Russell A.
This report covers work performed during the period of November 1994 through March 1996 on the design of a Space-borne Solar Vector Magnetograph. This work has been performed as part of a design team under the supervision of Dr. Mona Hagyard and Dr. Alan Gary of the Space Science Laboratory. Many tasks were performed and this report documents the results from some of those tasks, each contained in the corresponding appendix. Appendices are organized in chronological order.
NASA Astrophysics Data System (ADS)
Adam, C.; Naya, C.; Sanchez-Guillen, J.; Wereszczynski, A.
We analyze the vector meson formulation of the Bogomol�nyi-Prasad-Sommerfield (BPS) Skyrme model in (3+1) dimensions, where the term of sixth power in first derivatives characteristic for the original, integrable BPS Skyrme model (the topological or baryon current squared) is replaced by a coupling between the vector meson ?? and the baryon current. We find that the model remains integrable in the sense of generalized integrability and almost solvable (reducible to a set of two first-order ordinary differential equations) for any value of the baryon charge. Further, we analyze the appearance of topological solitons for two one-parameter families of one-vacuum potentials: the old Skyrme potentials and the so-called BPS potentials. Depending on the value of the parameters, we find several qualitatively different possibilities. In the massless case, we have a parameter region with no Skyrmions, a unique compact Skyrmion with a discontinuous first derivative at the boundary (equivalently, with a source term located at the boundary, which screens the topological charge), and Coulomb-like localized solitons. For the massive vector meson, besides the no-Skyrmion region and a unique C-compact soliton, we find exponentially as well as power-like localized Skyrmions. Further, we find (for a specific potential) BPS solutions, i.e., Skyrmions saturating a Bogomolny bound (both for the massless and massive vector mesons), which are unstable for higher values of the baryon charge. The properties of the model are finally compared with its baby version in (2+1) dimensions and with the original BPS Skyrme model, contributing to a better understanding of the latter.
Recurrent Support Vector Machines
Matteo Gagliolo; Daan Wierstra; Faustino Gomez; IDSIA Galleria
Abstract Existing Support Vector Machines (SVMs) need pre-wired finite time windo ws to predict and classify time series. They do not have an internal state necessary to deal with sequences involving arbitrary long-term dependencies. Here we introduce the first recurrent, truly s equential SVM-like devices with internal adaptive states, trained by a novel method called EVOlution of systems with KErnel-based
Radiometric correction of scatterometric wind measurements
NASA Technical Reports Server (NTRS)
Use of a spaceborne scatterometer to determine the ocean-surface wind vector requires accurate measurement of radar backscatter from ocean. Such measurements are hindered by the effect of attenuation in the precipitating regions over sea. The attenuation can be estimated reasonably well with the knowledge of brightness temperatures observed by a microwave radiometer. The NASA SeaWinds scatterometer is to be flown on the Japanese ADEOS2. The AMSR multi-frequency radiometer on ADEOS2 will be used to correct errors due to attenuation in the SeaWinds scatterometer measurements. Here we investigate the errors in the attenuation corrections. Errors would be quite small if the radiometer and scatterometer footprints were identical and filled with uniform rain. However, the footprints are not identical, and because of their size one cannot expect uniform rain across each cell. Simulations were performed with the SeaWinds scatterometer (13.4 GHz) and AMSR (18.7 GHz) footprints with gradients of attenuation. The study shows that the resulting wind speed errors after correction (using the radiometer) are small for most cases. However, variations in the degree of overlap between the radiometer and scatterometer footprints affect the accuracy of the wind speed measurements.
Wind-tunnel modeling of hill and vegetation influence on wind power availability
David E Neff; Robert N Meroney
Forested hills and ridges pose a number of significant technical and environmental issues for siting wind turbines. The change in the wind profile across the top of the hill due to the presence or absence of trees and differences in roughness characteristics must be understood in order to develop accurate energy estimates. A three phase research program was undertaken to
Distributed Wind Evaluation Methodology
Thomas E. McDermott
The Utility Wind Interest Group (UWIG) has undertaken a Distributed Wind Impacts project, which has produced software tools, application guides, and case studies to evaluate distributed wind projects. The project size may range from 1.5 to 15 MW, or higher in the near future. Given a number and size of available utility-scale wind turbines, and a candidate site, the evaluation
W. E. Currah; G. W. Harper
A system for conversion of wind power to electrical energy is described. The system provides for use during a wide range of wind velocities by use of the following: an external deflection system consisting of baffles and peripheral turbulence creating walls designed to increase the wind velocity and to divert the wind stream to the aperture of the system; a
NSDL National Science Digital Library
US Department of Energy; Energy Efficiency and Renewable Energy (EERE)
This animation, from the US Department of Energy, discusses the advantages of wind power, the workings of a wind turbine, and wind resources in the United States. It also describes how wind power is used in small- and large-scale applications.
ERIC Educational Resources Information Center
Journal of College Science Teaching, 2005
This brief article describes a new global wind-power map that has quantified global wind power and may help planners place turbines in locations that can maximize power from the winds and provide widely available low-cost energy. The researchers report that their study can assist in locating wind farms in regions known for strong and consistent�
Danish Wind Industry Association
NSDL National Science Digital Library
Visitors to this non-profit site can access introductory information about wind turbines and the generation of electricity by wind power. For kids, there is an interactive tour of a wind turbine. For older learners, there is a tutorial that covers all aspects of wind energy. The site is available in several languages, including French and Spanish.
Not Available
This book presents the papers given at a conference on wind turbines. Topics considered at the conference included resource assessment, wind tunnels, performance testing, aerodynamics, turbulence, fatigue, electric generators, wind loads, horizontal axis turbines, vertical axis turbines, Darrieus rotors, wind-powered pumps, economics, environmental impacts, national and international programs, field tests, flow models, feasibility studies, turbine blades, speed regulators, and airfoils.
Not Available
This book presents the papers given at a conference on wind turbines. Topics considered at the conference included resource assessment, wind tunnel testing, vertical axis turbines, wind turbine generators, aerodynamics, airfoils, wind loads, Darrieus rotors, economics, legislation, regulations, environmental impacts, national and international programs, fatigue testing, and horizontal axis turbines.
NSDL National Science Digital Library
Wind With Miller is a collection of classroom activities that provide good background information about wind energy. The site also provides students with opportunities to build small wind turbines, wind socks, and kites and has a section for teachers. There are a variety of exercises to use in the classroom provided on the site including topics such as small shaft, anemometer, and cooling systems.
R. H. Miller; M. Martinez-Sanchez; J. Dugundji; E. E. Larrabee; I. Chopra; T. Humes; S. Y. Chung; J. C. Gohard; J. T. Edwards
Various problems associated with the design of horizontal axis, low solidity, and high performance wind turbines are investigated. Wind turbine performance as determined from various elementary and more refined momentum theories, aerodynamic vortex theories for blade loadings including unsteady effects and wind shear velocity gradients, and nonlinear dynamic response of rotor blades including gravity and wind shear excitation were studied.
Towards an Optimal Noise Versus Resolution Trade-Off in Wind Scatterometry
NASA Technical Reports Server (NTRS)
Williams, Brent A.
A scatterometer is a radar that measures the normalized radar cross section sigma(sup 0) of the Earth's surface. Over the ocean this signal is related to the wind via the geophysical model function (GMF). The objective of wind scatterometry is to estimate the wind vector field from sigma(sup 0) measurements; however, there are many subtleties that complicate this problem-making it difficult to obtain a unique wind field estimate. Conventionally, wind estimation is split into two stages: a wind retrieval stage in which several ambiguous solutions are obtained, and an ambiguity removal stage in which ambiguities are chosen to produce an appropriate wind vector field estimate. The most common approach to wind field estimation is to grid the scatterometer swath into wind vector cells and estimate wind vector ambiguities independently for each cell. Then, field wise structure is imposed on the solution by an ambiguity selection routine. Although this approach is simple and practical, it neglects field wise structure in the retrieval step and does not account for the spatial correlation imposed by the sampling. This makes it difficult to develop a theoretically appropriate noise versus resolution trade-off using pointwise retrieval. Fieldwise structure may be imposed in the retrieval step using a model-based approach. However, this approach is generally only practical if a low order wind field model is applied, which may discard more information than is desired. Furthermore, model-based approaches do not account for the structure imposed by the sampling. A more general fieldwise approach is to estimate all the wind vectors for all the WVCs simultaneously from all the measurements. This approach can account for structure of the wind field as well as structure imposed by the sampling in the wind retrieval step. Williams and Long in 2010 developed a fieldwise retrieval method based on maximum a posteriori estimation (MAP). This MAP approach can be extended to perform a noise versus resolution trade-off, and deal with ambiguity selection. This paper extends the fieldwise MAP estimation approach and investigates both the noise versus resolution trade-off as well as ambiguity removal in the fieldwise wind retrieval step. The method is then applied to the Sea Winds scatterometer and the results are analyzed. This paper extends the fieldwise MAP estimation approach and investigates both the noise versus resolution trade-off as well as ambiguity removal in the fieldwise wind retrieval step. The method is then applied to the Sea Winds scatterometer and the results are analyzed.
Variability of Load and Net Load in Case of Large Scale Distributed Wind Power
Holttinen, H.; Kiviluoma, J.; Estanqueiro, A.; Gomez-Lazaro, E.; Rawn, B.; Dobschinski, J.; Meibom, P.; Lannoye, E.; Aigner, T.; Wan, Y. H.; Milligan, M.
Large scale wind power production and its variability is one of the major inputs to wind integration studies. This paper analyses measured data from large scale wind power production. Comparisons of variability are made across several variables: time scale (10-60 minute ramp rates), number of wind farms, and simulated vs. modeled data. Ramp rates for Wind power production, Load (total system load) and Net load (load minus wind power production) demonstrate how wind power increases the net load variability. Wind power will also change the timing of daily ramps.
Assessment of Atmospheric Winds Aloft during NASA Space Shuttle Program Day-of-Launch Operations
NASA Technical Reports Server (NTRS)
Decker, Ryan K.; Leach, Richard
The Natural Environments Branch at the National Aeronautics and Space Administration s Marshall Space Flight Center monitors the winds aloft at Kennedy Space Center in support of the Space Shuttle Program day of launch operations. High resolution wind profiles are derived from radar tracked Jimsphere balloons, which are launched at predetermined times preceding the launch, for evaluation. The spatial (shear) and temporal (persistence) wind characteristics are assessed against a design wind database to ensure wind change does not violate wind change criteria. Evaluations of wind profies are reported to personnel at Johnson Space Center.
Exhaust Nozzle Plume Effects on Sonic Boom Test Results for Vectored Nozzles
NASA Technical Reports Server (NTRS)
Castner, Raymond
Reducing or eliminating the operational restrictions of supersonic aircraft over populated areas has led to extensive research at NASA. Restrictions were due to the disturbance of the sonic boom, caused by the coalescence of shock waves formed off the aircraft. Recent work has been performed to reduce the magnitude of the sonic boom N-wave generated by airplane components with a focus on shock waves caused by the exhaust nozzle plume. Previous Computational Fluid Dynamics (CFD) analysis showed how the shock wave formed at the nozzle lip interacts with the nozzle boat-tail expansion wave. An experiment was conducted in the 1- by 1-foot Supersonic Wind Tunnel (SWT) at the NASA Glenn Research Center. Results show how the shock generated at the nozzle lip affects the near field pressure signature, and thereby the potential sonic boom contribution for a nozzle at vector angles from 3 to 8 . The experiment was based on the NASA F-15 nozzle used in the Lift and Nozzle Change Effects on Tail Shock experiment, which possessed a large external boat-tail angle. In this case, the large boat-tail angle caused a dramatic expansion, which dominated the near field pressure signature. The impact of nozzle vector angle and nozzle pressure ratio are summarized.
A survey on wind power ramp forecasting.
Ferreira, C.; Gama, J.; Matias, L.; Botterud, A.; Wang, J. (Decision and Information Sciences); (INESC Porto)
The increasing use of wind power as a source of electricity poses new challenges with regard to both power production and load balance in the electricity grid. This new source of energy is volatile and highly variable. The only way to integrate such power into the grid is to develop reliable and accurate wind power forecasting systems. Electricity generated from wind power can be highly variable at several different timescales: sub-hourly, hourly, daily, and seasonally. Wind energy, like other electricity sources, must be scheduled. Although wind power forecasting methods are used, the ability to predict wind plant output remains relatively low for short-term operation. Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, wind power's variability can present substantial challenges when large amounts of wind power are incorporated into a grid system. A critical issue is ramp events, which are sudden and large changes (increases or decreases) in wind power. This report presents an overview of current ramp definitions and state-of-the-art approaches in ramp event forecasting.